Doctor Who is, was, and possibly always will be, the longest-running science fiction television series ever aired. The BBC-produced series ran from 1963 to 1989 (with one-off specials in 1993, 1996 and 1999), and ran again from 2005 onward. To this day, it retains tremendous worldwide fan support.

Who is Doctor Who

Although he is generally known as The Doctor, there is some evidence to suggest that the lead character's name is in fact 'Doctor Who', though many fans deny this. He often claims that his real name is unpronounceable in any Earth tongue. Occasionally he has been known by the pseudonym 'John Smith', a name he acquired by accident¹.

The Doctor is a time traveller of almost immortal standing, who travels through time in his TARDIS². This 'machine' looks like an old-fashioned, worn-down British Police Call box, but once inside the dimensions appear infinite. The reason for this is that the TARDIS once had the ability to blend in with its surroundings until, during a trip to 1960s London, it got stuck in the form of the police box.

The Doctor(s)

The Doctor is something of an enigma and there remains much that we still do not know about him. What is certain is:

• He is not human. When he first appeared, this was an element that was more hinted at than said outright. However, there has been suggestions that he is half-human on his mother's side (according to a line in the TV movie), though this might just have been a joke.

• At the beginning of the series, the Doctor was accompanied on his travels by his granddaughter, Susan. Though Susan's own parentage has never been discussed, and despite the discomfort experienced by some fans at the thought of their hero indulging in sexual reproduction, there is nothing to suggest that Susan is not in fact the direct descendant of the Doctor.

• Aside from Susan, nothing is known about other members of the Doctor's family. He only ever refers to them in a melancholy fashion, and at one point ('The Curse of Fenric'), he states that he does not know whether they are alive or dead. The Tenth Doctor hinted that he was once a father and that he doesn't have a brother any more, though it's not clear if these were flippant remarks or intended to be taken seriously.

• Three years into the series, it was revealed that, in times of physical crisis, the Doctor can regenerate his body into a new form - effectively, he becomes a new person with the memories of his previous selves. To date, this has happened nine times, producing ten very different, yet similar, Doctors.

• At the end of the era of the second Doctor, he confided in his companions that he was a member of a race of powerful beings known as 'Time Lords'. By the time of his seventh persona, even this was called into some doubt; it was suggested that he had either evolved into something other than 'just another Time Lord' or else had been lying about his Time Lord status all along.

• In the words of the second Doctor, theoretically, he can 'live forever... barring accidents'. This was later qualified in the story 'The Deadly Assassin' - each Time Lord has an initial lifespan of 13 incarnations. There has been some suggestion that additional regeneration cycles can be arranged - as discussed in 'The Five Doctors', in which the Time Lords make such an offer to the Master - and indeed there is some evidence that this has indeed happened some time in the Doctor's own past (one explanation for a short sequence in 'The Brain of Morbius' in which faces that are possibly meant to be earlier Doctors are shown). In 'Death of the Doctor', an episode of the spin-off series The Sarah Jane Adventures, the Eleventh Doctor told Clyde that he could regenerate 507 times, though again, it's not clear if he was being serious at the time.

• When the Doctor regenerated for a second time, it was revealed that he had two hearts. Whether or not the additional heart had been present in either of his previous bodies has not been confirmed.

• Towards the end of the third Doctor's run, we learned that he comes from the planet Gallifrey³.

• Having rejected the non-interventionist ways of his people, the Doctor is classed as a renegade. He refuses to conform to Time Lord 'laws', and constantly interferes in the affairs of other planets, especially when he sees evil and injustice that must be fought.

• The Doctor has a number of other alien abilities. He is vaguely telepathic, or at least can share information with other Time Lords or even - on very rare occasions - with his past selves. He can perform martial arts, including Venusian aikido and can stop his hearts and entire respiratory system at will for short periods.

Genesis - The First Doctor

Doctor Who began as an on-going serial that ran almost all year round (bar a few weeks off in the summer). The serial was divided into series, or stories, which in turn were divided into episodes. Though in later years the average length for a story was four episodes, this really only became the norm half-way through the series history; originally, stories could be six, seven or even 12 episodes.

The series was originally conceived as something to bridge the afternoon sports coverage on Saturday afternoons with the evening family viewing (which at the time included a pop music show called Juke Box Jury). Sydney Newman, head of Drama Serials at BBC Television, commissioned a group of writers to come up with a series that would combine drama with education, suitable for a family audience. Alice Frick, Donald Wilson, John Braybon and CE 'Bunny' Webber between them came up with the idea of a time traveller and his assorted crew, and with the help of writers Anthony Coburn, Terry Nation⁴, David Whittaker and others, and under the leadership of bright young producer Verity Lambert, the show began to take shape. With all of the people involved in its birth, we can see that it's a little unfair that it's Sydney Newman who is generally credited as the show's 'creator'.

To promote an air of family acceptability, the production team assembled a cast of characters that included the Doctor's 15-year-old granddaughter Susan (played by 23-year-old Carole-Ann Ford), schoolteachers Ian Chesterton and Barbara Wright (played by William Russell and Jacqueline Hill) and the Doctor himself, played by William Hartnell, famous mainly for playing gruff military types in The Army Game and the first Carry On... movie, Carry On Sergeant.

The series finally hit the air with the episode 'An Unearthly Child'⁵, transmitted just after 5.15pm on Saturday, 23 November, 1963. Though the show was a moderate success to begin with, it was with its second serial, the seven-part story 'The Mutants'⁶ that the series really took off. This boasted the first appearance of those mechanical despots - the Daleks!

Created by Terry Nation, and designed by BBC staff designer Raymond Cusick, the Daleks were in fact mutated blobs encased in metal life-support systems. They were completely alien to look at, with their vaguely parabolic bodies that sported a solitary eye stalk at the top, an extendable arm and suction cup and a short ray gun positioned in the middle section at the front, and a series of spheres around the skirting. But it was their grating metallic voices that made the most lasting impression - stilted, jarring speech that was as horrific to listen to as it was easy to imitate in the playground. Killed off at the end of their first appearance, they were subsequently revived again and again for 25 years whenever the ratings demanded it.

William Hartnell played the Doctor for three years, a total of 29 stories, which translates into over a hundred individual episodes. The high-point of these first few years was the 12-part serial The Daleks' Masterplan, in which the Daleks tried to take over the galaxy, a member of the Doctor's own mysterious race made an appearance (the monk - played by Peter Butterworth - who had first appeared in an earlier story) and one of the Doctor's own companions was brutally killed⁷.

In 1966, William Hartnell was suffering from ill health. Though the production team wanted to continue making the show, they realised that Hartnell was simply not well enough to continue and, despite being just 58, would have to retire from the part he loved so much. They took the then-bold step of casting another actor in the same role. Rather than try for an impersonation of Hartnell, which was felt would have been disrespectful towards the show's outgoing star, it was decided that the new Doctor Who would be a completely different character. So it was that just two stories into the show's fourth year⁸, the Doctor's body wore out and he 'regenerated' into a form suspiciously like that of character actor Patrick Troughton.

Time of Growth - The Second Doctor

Troughton's Doctor was a complete contrast to Hartnell's. Where the First Doctor had been quiet, reserved, and slightly tetchy, the Second Doctor acted like a clown to fool people into underestimating him. He was fond of lurking in the background, only stepping forward when required. Discarding the elegant Victorian suit of his predecessor, Troughton's wardrobe of baggy checked trousers and oversized jacket gave him the appearance of a tramp, something that always worked in his favour when villain after villain dismissed him as nobody to worry themselves about.

During the time of the second Doctor, Doctor Who gained popularity in leaps and bounds. Two films of Doctor Who were made around this time. Doctor Who and the Daleks and Daleks' Invasion Earth: 2150AD featured Peter Cushing as the Doctor and were (very loose) adaptations of the first two Dalek stories.

By 1969, the ratings for the show had become worryingly low. Troughton had decided to leave and so it looked as if it might be time for the Doctor to regenerate again. In Troughton's last story as the Doctor, 'The War Games' (a mammoth ten-part adventure), the Doctor's race - the all-powerful Time Lords - were introduced in the final episode. The Time Lords put the Doctor on trial for interfering in the lives of others (thus endangering the time continuum), which, we're told, was against the very Time Lord laws that had made the Doctor leave his people in the first place. His punishment is exile to Earth, and a forced regeneration.

Colour in Exile - The Third Doctor

In 1970, Doctor Who returned with famous and popular actor Jon Pertwee as the Doctor. For the first time, Doctor Who appeared in colour on our TV screens, a technological expense that necessitated a number of changes to the show. The episode count was almost halved and the dizzy alien locations were replaced by more Earth-bound stories - explained in the narrative by the Doctor's exile to the planet. A supporting cast was introduced in the form of UNIT (United Nations Intelligence Task Force), headed by Brigadier Alistair Gordon Lethbridge-Stewart (a character that had been introduced two years earlier in 'The Web of Fear'). The Doctor is invited to work with UNIT in return for scientific equipment that the Doctor hopes will enable him to find a way to escape Earth.

In contrast to Troughton, the Third Doctor was flamboyant, arrogant, a flashy dresser, and was described derogatorily as a 'dandy'. During the Pertwee era, Doctor Who became one of the most popular shows in England.

During season eight, Pertwee's second year, a new villain was introduced - a renegade Time Lord, like the Doctor, but one who interferes for the purpose of evil who was known 'universally' as The Master. Played by Roger Delgado, he became a popular recurring character whose nefarious plans were inevitably thwarted by our hero. Despite playing the most evil man in the universe, Delgado himself was a much-loved man whose charm and good nature made him a number of genuine friends on the Doctor Who team. When Delgado died tragically in a car crash just months before he was due to make his final appearance on the show, the toll on the cast and production team was too great. Combined with the departure of his companion Jo, played by Katy Manning, and the imminent departure of both the producer and script writer, Jon Pertwee decided he'd had enough and in May, 1974, viewers saw him regenerate into Tom Baker.

The only problem was, no-one actually knew who Tom Baker was...

Three in One - The Fourth Doctor

Though at his peak, Tom Baker would become the most recognisable actor on British TV, that was not the case when he first took on the role. Indeed, at the time he was cast, he had taken on a job working on a building site as the acting roles had dried up - despite the fact that his most recent film, The Golden Voyage of Sinbad, was being shown in a cinema just round the corner from the site he was working on.

What helped make Baker such a success was the fact that he was an imposing figure. Tall, with a mop of curly brown hair, huge, staring eyes and a costume that included a huge, 16-foot woollen scarf, he was a man who stood out in a crowd. Though he would go on to play the role for a record seven years, he managed to do this by effectively changing his approach to the character twice during the run. Initially, his was quite a serious character, peppered with the odd witty line. As time went on and he became more comfortable in the part, he became more zany and unpredictable. Finally, in his last year, he became sombre and doom-laden, an approach which some have attributed to the producer of his final years, John Nathan-Turner (known as JN-T), who took the decision to tone down the comedic sides of the show and made it more 'grown-up'.

As far as most of the general public are concerned, Baker's was the definitive portrayal. Having been the Doctor longer than anyone else, he left his mark on the show to the extent that it was difficult for anyone to follow him. It was during his era that the character Leela, a leather-clad savage, was introduced, as well as the gimmicky robot dog called, appropriately, K-9 (canine, geddit?!).

Finally, and some have suggested reluctantly, Baker decided to leave. In the final story of season 18, entitled 'Logopolis', the Doctor is killed after falling from a massive radio tower where he was trying to defeat the Master (who himself had regenerated... ish, in the form of Anthony Ainley). The season ended with the eyes of a new Doctor opening up...

Age Masked by Youth - The Fifth Doctor

The Fifth Doctor's era is hard to classify. Peter Davison (famous for his part on the long-running series All Creatures Great and Small) was the Fifth Doctor, starting with his brief appearance at the end of 'Logopolis' in 1981 and continuing with his first full season in January 1982. Described by some as 'an old man trapped in a young man's body', his manner seems more human, more vulnerable and he seems to care for others far more than even his predecessors. Unlike Tom Baker's Doctor, when the viewer was confident and safe knowing the Doctor would always come out in the end, there was an edge to the Davison era. It seemed as if the bad guys were bigger and better while the Doctor was smaller and weaker. No story illustrates this point better than 'Earthshock', which saw the unexpected death of the Doctor's companion Adric, the first time a companion had been killed since 1965.

Though the show had always been shown in roughly the same timeslot on Saturday evenings, the Davison era saw a move for the show to mid-week with episodes shown twice a week, a decision some saw as the BBC schedulers testing the best slots for a twice-weekly soap opera they were planning (which eventually arrived in 1985 in the form of EastEnders). However, after three years, Davison decided to leave to avoid being typecast. In Davison's last story ('The Caves of Androzani', 1984), the Doctor and his companion Peri contract a fatal disease - spectrox toxaemia. The Doctor gives the only antidote to Peri, then collapses onto the floor. When he rises again, it was with the face of Colin Baker... whether the viewers liked it or not!

Turbulence - The Sixth Doctor

Actor Colin Baker took over from Peter Davison in 1985, and was a complete contrast as the latest Doctor. Playing with the audience's expectations of Baker from the 1970s series The Brothers, in which he played the evil Paul Merroney, Colin's Doctor appeared uncaring, unsympathetic, extremely arrogant, conceited, sometimes a coward, and generally unpredictable. Just as he'd cast someone completely different to Tom Baker in the form of Davison, producer John Nathan-Turner selected Colin Baker to be in contrast to his predecessor - the quiet, sympathetic fifth Doctor made way for the brash, loud, tempestuous sixth.

This new type of Doctor was created to accentuate the alien nature of the character. However, it proved extremely unpopular. Though the ratings for his first full season (which once more returned the show to the Saturday evening slot) were not disastrously low, complaints about the show's violence and a general dislike of its new leading man led the BBC to 'rest' the series for 18 months. Much to the fans' joy, Doctor Who did return and Colin was still the Doctor, but the fans' celebrations were short-lived when it was announced that the episode count would be further cut to an all-time low, season 23 would be just 14 25-minute episodes long.

This season was unique; the production team took the decision to make it as one 14-part story⁹ entitled 'The Trial of a Time Lord'. Sadly, the series was a victim of a slump in the BBC's Saturday evening scheduling as ratings were almost half that of its previous year, at an average of just 5 million viewers. Once again, the future for the series looked bleak, until the BBC made a difficult, and largely unpopular decision. Against his wishes, Colin Baker was sacked and another actor hired in his place.

Stiff Competition - The Seventh Doctor

Sylvester McCoy, at the time best known for his slapstick comedy routines that involved ferrets down his trousers and six-inch nails up his nose, was perhaps an unusual choice for the seventh Doctor Who. But despite some fan resistance, the series continued for three more years - admittedly in a time slot it couldn't hope to shine in, opposite ITV's top-rated soap opera, Coronation Street.

From 1987 until 1989, the show went through a series of radical rethinking. The Doctor was given a new companion, a tomboy called Ace (played by Sophie Aldred), and the focus of the show became the Doctor taking Ace to face her greatest fears across the universe, in an unusual reworking of the Pygmalion/My Fair Lady theme. During this period, Doctor Who arguably had some of its best stories, characters, and concepts since the mid-1970s. With a new, fresh writing team who shared ideas and drove the series in a new direction, it looked as if Doctor Who's 1990 season would be its strongest in years. Sadly, though, this season never happened.

John Nathan-Turner had, by 1989, been the show's producer for almost a decade. Although he had been looking to move on from the series for at least five years, it always seemed to him that he was being kept on Doctor Who because no-one else wanted to produce it. When he finally resigned in 1989, his fears were proved right; no-one was allotted to replace him and all of the ideas that the writing team were developing remained unfulfilled. In the end, the show went off the air not with a bang but a murmur that it would return 'when the time was right'.

Faith, Hope and Charity

By 1990, very little BBC drama was actually made by the BBC themselves as the corporation commissioned independent companies to make the shows for them. For a time, it seemed likely that if Doctor Who had any future at all it would be via the independent route. While different companies submitted bids to be the new caretakers of the series, the Old Guard had one last shout under BBC control. In 1993, as part of the special annual Children In Need fundraiser week (and coinciding with Doctor Who's 30th anniversary), the BBC produced two five-minute episodes of a special Doctor Who called 'Dimensions In Time'. The story featured the third through seventh Doctors, as well as guest appearances by former companions all pitting their wits against the evil Rani (a villainess who had first appeared during Colin Baker's era who was played by Kate O'Mara). Boasting innovative new 3-D imagery, and combining Doctor Who's legend with EastEnders (!), it was painfully ironic that this spoof adventure was both one of the highest-rated (with 14 million viewers) and most well-publicised (thanks to a front cover on the Radio Times magazine) in the show's history. Ironic, as it was almost universally loathed by the fans. It did, however, help raise millions of pounds for the Children in Need appeal.

Reborn in the USA - The Eighth Doctor

In 1995, Fox (an American entertainment network) obtained the rights to make a one-off Doctor Who movie with a view to a possible series. The movie was broadcast in the spring of the following year, with Sylvester McCoy handing over the keys to the TARDIS to popular British actor Paul McGann (Sylvester McCoy had a brief guest appearance in the beginning of the movie, so the Doctor could 'die' and regenerate into McGann). The telefilm was impressive in almost every way; it had a big budget, a good characters, and good acting. Though there were some problems with a confused script, none of these elements could be held solely attributable to the project's lack of success. For that, we have to look to a rotund, sarcastic comedian by the name of Roseanne. The premiere of the Doctor Who movie clashed with the final episode of Roseanne's long-running sitcom. As such, Fox were disappointed by the 12.2 million viewers that it received. When the film was broadcast in the UK some weeks later, it was at the beginning of Summer (when ratings traditionally begin to dip) and after the video of the film had been available to fans for two weeks. Despite this, the film gained a respectable 9 million viewers. Fox's subsequent lack of interest in continuing the project brought Paul McGann's disappointingly brief reign as Doctor Who to an end.

The New Face of Who... Mr Bean

As part of the 1999 Comic Relief fundraiser night, the BBC produced four five-minute episodes of a specially-made comedy Doctor Who. Called 'The Curse Of Fatal Death', it featured Rowan Atkinson (famous as Blackadder and Mr Bean) as the Doctor. Written by Steven Moffat - who created the children's TV show Press Gang and the comedy series Joking Apart, Chalk and Coupling - it was very funny and avoided many of the clichés that other spoofs have resorted to while still remaining faithful to the show's history. Playing with the concept of regeneration, the short adventure saw the Doctor played by Atkinson, Richard E Grant, Jim Broadbent, Hugh Grant and finally... Joanna Lumley. Despite being a comedy spoof, 'The Curse of Fatal Death' was highly regarded by fans as well as contributing hugely to the Comic Relief appeal.

A Future Online?

Since 2001, BBCi had hosted a number of online dramas with very basic animation, including adventures for Sylvester McCoy, Colin Baker and Paul McGann. But to celebrate the show's 40th anniversary in November 2003, BBCi have cast a new Doctor Who for a brand new, fully-animated adventure. Actor Richard E Grant (who previously played the Doctor in the spoof 'The Curse of Fatal Death') took on the mantle of the ninth official Doctor. Sadly, like Paul McGann before him, Grant's portrayal in animated form was also a one-off, and subsequent events would rob him of his official status.

The Continuing Adventures - The Fans

In recent years, many of the viewers who watched the series as children have grown up to be professional writers, directors, actors and producers. Thanks largely to their efforts, the Doctor's adventures continue in books, comic strips and in original audio dramas utilising the fifth, sixth, seventh and eighth Doctors and their companions. Spin-offs have included Dalek Empire and series shaped around Sarah Jane Smith and UNIT.

The Trip of a Lifetime - the Ninth Doctor

With the Doctor surviving across all manner of media, it's true to say that for most fans the one place they wanted to see the good Doctor above all others was back on TV in his own series. In the autumn of 2003, it was announced that he would be doing just that. Thanks to a team of people headed by writer Russell T Davies, the Doctor would be returning to Saturday nights as part of a big-budget revival of the series. In March 2004 it was announced that the new Doctor would be none other than Christopher Eccleston, an actor famous for his work on TV shows such as Cracker and Our Friends in the North and films like Jude, Elizabeth and 28 Days Later. His companion, Rose Tyler, is played by Billie Piper, a former pop star whose previous acting roles include the high-profile reworking of Chaucer's Canterbury Tales.

With a team of writers whose background includes award-winning drama and comedy on stage and screen, a string of impressive guest stars including Simon Callow, Penelope Wilton and Zoe Wanamaker, and a budget befitting a prime-time TV series for the first time in its long history, expectations were high for the 2005 show. With over ten million viewers tuning in, the series was declared a success and soon after it began a Christmas special and a second series were announced as being in production. But without Eccleston!

... and the Tenth!

Intent on doing just one series to help kick-start the series for a new generation, Christopher Eccleston's decision to leave after just 13 episodes was leaked to the press ahead of the planned announcement, meaning that a surprise ending to the series was spoiled somewhat. The fans were of course disappointed that he wouldn't be staying around for longer (and indeed some of them were positively foaming at the mouth at what they viewed as a 'betrayal'). However, many of them were grateful for the fact that he'd helped bring the series back in the first place - and of course it meant that the new fans would get to see their own regeneration.

After weeks of speculation, the tenth Doctor Who was unveiled at midnight on 16 April as David Tennant, an actor who had appeared in such dramas as Blackpool, a live performance of The Quatermass Experiment and the three-part drama Casanova. A life-long fan of the series, Tennant was quoted in the press release as saying: 'I am delighted, excited and honoured to be the tenth Doctor! I grew up loving Doctor Who and it has been a lifelong dream to get my very own TARDIS.'

Bow Ties are Cool - The Eleventh Doctor

Seen to regenerate on New Year's Day, 2010, the Tenth Doctor gave way to the Eleventh. Matt Smith became the youngest actor to date to play the role, having previously appeared in the TV dramas Ruby in the Smoke and Party Animals.

The Doctor's Gadgets

The Doctor's possessions include:

• A Sonic Screwdriver - a device first seen in 'Fury from the Deep' in 1967 that can be used to open locked doors, scramble sensors, detonate sensitive bombs, reprogram circuits, and undo screws with sonic vibrations. A handy get-out clause for writers, the device was written out in the 1982 adventure 'The Visitation', though the Doctor appeared to have acquired a new one by the time of the 1996 TV movie, and the Ninth, Tenth and Eleventh Doctors certainly have one each.

• Bessie - The Doctor's bright yellow vintage roadster vehicle that he acquired during his exile on Earth in the 1970 story 'Doctor Who and the Silurians'. Top speeds unknown.

• K-9 - Faithful, dog-like, robotic companion of the Fourth Doctor, K-9 comes when called, shoots laser blasts from his nose, and serves as an early warning system for the absent-minded Doctor. He also looks a bit like a dog and is immensely smug. Three different models exist of K-9, each residing with a different former companion of the fourth Doctor's: one remains on Gallifrey with Leela; one was last seen in another universe with Romana; and one lives with investigative journalist Sarah-Jane Smith.

• Jelly Babies - Infant-shaped jelly confectionery that hit the spot and are useful for defusing a tough situation.

The Time Lords

Who are they? Time Lords come from the planet of Gallifrey, near the centre of the Galaxy. Not everybody on Gallifrey is a Time Lord. They appear to be a sort of higher caste who rule over the rest of the native Gallifreyans. Time Lords are distinguishable from the rest of the planet by the fact that they control the power of time travel, are usually incredibly pompous and are rarely seen outside of their protective dome, the Capitol. They are the only known people in the universe who have absolute power over time. The Daleks and the Sontarans also have time travel technology, but it is not up to the standard of that available to the Time Lords.

The Beginning: So the legends go, Time Lord society is shaped by two great figures, Omega and Rassilon. This part of Time Lord history is relatively unknown, but it appears the Gallifreyans at the time were great engineers who sought to uncover the mysteries of time travel. Omega was one of the greatest scientists of the time, a 'Stellar Engineer' - his science involved the manipulation of stars. In order to commence time travel experiments, a huge source of power was required. Omega created this by way of a supernova, which gave the Gallifreyans all the power they needed to start their experiments. Unfortunately, Omega was caught in the explosion of the star, and presumed killed. But that is another story...

The Dark Years: So called, because of corruption that was rife in Time Lord society at this point. Time Lords had immense powers, which they misused. They interfered with many planets, attempting to advance their technological development, whose civilisations often mistook them for Gods. They also used other species for sport. There is an area on Gallifrey called the Death Zone, which was used as a sort of arena. They kidnapped other beings and set them in this range of mountains to fight each other to the death. After the Minyan race almost died out as a result of Time Lord interference, the Time Lords adopted a policy of non-interference.

Rassilon: Often referred to as 'the greatest single figure in Time Lord history'. It was he who put an end to the 'games' and closed down the Death Zone. Rassilon also restructured the whole of Time Lord society, got rid of the corruption and generally turned a group of greedy, interfering demi-gods into a race of quiet and contemplative intellectuals, content merely to observe the Universe. From this point on, interfering in other planets was one of the greatest crimes in Time Lord law. This is why the Doctor is often thought of as a criminal, even though certain sections of the Time Lords are not adverse to using him for their own ends.

Rassilon's greatest achievement was the Eye of Harmony. Despite Omega's sacrifice, it is Rassillon who is remembered as the creator of the Eye, a black hole that provides the Time Lords with infinite power. The Eye of Harmony is stored in a specially designed obelisk underneath the Panopticon, which is a sort of court for Time Lords.

Despite all this, not much is known about Rassilon. There are many rumours that he was actually evil, and it was in reaction to his diabolic nature that the Time Lords changed. Certainly, his tomb is in the Death Zone, hardly a suitable burial place for the man who closed it down. Possibly this was just a clever ploy by him. Rassilon is a sort of immortal figure, and he might have sealed himself into the Death Zone to protect this technology from any greedy people who might seek it. This certainly seems likely, given the history revealed in 'The Five Doctors'.

The High Council: The ruling council of the Time Lords, it usually consists of three or four core members. The Doctor has been elected President of this council twice, and offered the presidency on another occasion. On all occasions, he has refused the responsibility.

Beyond the Time Lords: The only power beyond the Time Lords are the Eternals, hungry scavengers from outside time, who feast on the minds of 'Ephemerals'. Above the Eternals are the Black and White Guardians, who are the supreme forces of Good and Evil in the Universe. They appear very little in Doctor Who, but whenever they do, the stakes become frighteningly high...

A feature of the series post-2005 has been a back-story involving a 'Time War' between the Daleks and the Time Lords. Both races were wiped out; the sole survivor being the Doctor - or so it appeared. Later, a solitary Dalek is discovered to have fallen through a gap in time; a cult of four Daleks escaped the war by hiding in a null-space called 'the void'; Davros was rescued from the war by one of the cult members; and the Time Lords are revealed to have survived, trapped within the war and using every method possible to attempt an escape. They were last seen, led by Rassilon, being pushed back into their Time War prison by the Master.

The Aliens

At various times Doctor Who and his helpers faced: The Ice Warriors, Giant Maggots, Silurians and Sea Devils, The Master, Cybermen, Daleks, Sontarans, The Autons, The Fendahl, The Krotons, Davros, The Axons, The War Machines, Quarks, Ogrons, The Kandyman, the Spiders of Metabelis 3, Aggedor, Omega, Draconians, Marshmen, Menoptra, Bok, The Terileptils, The Yeti, Zygons, The Krynoid, The Robots of Death, Cybermats, The Wirrn, The Nimon... and many, many more.

Further Reading

• h2g2's Doctor Who  Episode Guide.

• Missing Episodes of Doctor Who

• The Doctor Who Title Sequence