Fourth Doctor
The Fourth Doctor is an incarnation of the Doctor, the protagonist of the British science fiction television series Doctor Who. He is portrayed by Tom Baker.
Within the series' narrative, the Doctor is a centuries-old alien Time Lord from the planet Gallifrey who travels in time and space in the TARDIS, frequently with companions. At the end of life, the Doctor regenerates; as a result, the physical appearance and personality of the Doctor changes. Preceded in regeneration by the Third Doctor, he is followed by the Fifth Doctor.
Baker portrays the Fourth Doctor as a whimsical and sometimes brooding individual whose enormous personal warmth is at times tempered by his capacity for righteous anger. His initial companions were the journalist Sarah Jane Smith, who had travelled with his previous incarnation, and Surgeon-Lieutenant Harry Sullivan of UNIT. His later companions were the warrior Leela, robotic dog K9, fellow Time Lady Romana, teen mathematical genius Adric, teen alien aristocrat Nyssa, and Australian flight attendant Tegan Jovanka.
Baker portrayed the character for seven consecutive seasons, which remains the longest tenure of any actor to portray the lead, counting both the classic and new series. Baker's tenure as the Doctor is highly regarded among fans of the show and he is considered one of the icons of Seventies British culture.
Appearances
Television
After contracting radiation poisoning from the crystals of the planet Metebelis 3, the Third Doctor makes his way back to UNIT headquarters in the TARDIS, where the Time Lord K'Anpo Rimpoche aids him in regenerating.In his new incarnation, the Doctor is eager to leave Earth in favour of exploration, thus drawing back from continuous involvement with UNIT. He has also grown tired of working for the Time Lords. Despite attempts to avoid them altogether, the Time Lords continue to send him on occasional missions, including an attempt to prevent the creation of the Daleks, during which he also meets Davros. The Doctor travels with journalist Sarah Jane Smith, whom he had befriended prior to his regeneration, and, for a time, with UNIT Surgeon-Lieutenant Harry Sullivan.
After a battle with Zygons in Scotland, Harry decided that taking the train was safer than the TARDIS, which the Doctor and Sarah Jane chose to try to make an appointment in London. Instead they ended up on the planet Zeta Minor, located at the far edge of the known universe. From this point on, the Doctor and Sarah Jane travelled alone.
The Doctor's companionship with Sarah Jane came to an end when he received a telepathic summons to Gallifrey, as humans were not then allowed on the planet. The summons turns out to be part of a trap set by his enemy the Master. The renegade Time Lord has used up all his regenerations and has degenerated into little more than a withered skeletal husk. The Doctor is framed for the assassination of the President of the High Council of Time Lords and put on trial. To avoid execution, the Doctor invokes an obscure law and declares himself a candidate for the office, giving himself the time he needs to prove his innocence and expose the real culprit. This ultimately results in a climactic battle with the Master.
The Doctor is seen to travel alone for the first time, returning to a planet he had visited centuries before. During his previous visit, he had accidentally imprinted his own mind on a human colony ship's powerful computer, Xoanon, leaving it with multiple personalities. On his second visit the Doctor is now remembered as an evil god by the descendants of the colonists, some of whom had become a warrior tribe called the Sevateem. After the Doctor cures the computer, one of the Sevateem, Leela, joins him on his travels. The Doctor brings the intelligent but uneducated Leela to many locales in human history, teaching her about science and her own species' past. In Victorian London, the pair encounters the magician Li Hsien Chang and his master, the self-styled Weng-Chiang. Weng-Chiang is revealed to be a time-jumping criminal from the Earth's distant future.
Later, the Doctor and Leela visit the Bi-Al Foundation medical centre, where they acquire the robot dog K-9. While K-9 is malfunctioning, a time distortion leads the TARDIS back to contemporary rural England. While investigating the distortion, he and Leela are confronted by an ancient being that feeds on death from Time Lord history, called the Fendahl. Eventually, the Doctor returns to Gallifrey and declares himself Lord President, based on the election held during his previous visit. This is in fact a ploy to reveal and defeat a Vardan invasion plan, which led to the unexpected consequence of leaving Gallifrey open to attack by the Sontarans. In the aftermath Leela and K9 decide to remain on Gallifrey. The Doctor comforts himself by producing K9 Mark II.
Shortly afterward, the powerful White Guardian assigns the Doctor the task of finding the six segments of the Key to Time, sending a young female Time Lord named Romana to assist him. The two Gallifreyans travel to a variety of planets, encountering strange and unusual allies and enemies, gathering the six segments and defeat the equally powerful Black Guardian, who sought the Key for himself. After the conclusion of the quest, Romana regenerates into a new form .
In an effort to evade the Black Guardian, the Doctor installs a "Randomiser" in the TARDIS so that not even the Black Guardian can anticipate where they go. Ironically, the first place the Randomiser sends them is the home planet of the Daleks, Skaro. Perhaps because of this, the Doctor begins frequently over-riding the machine, first travelling to Paris for a holiday, only to get caught up in an alien scheme to steal the Mona Lisa. He eventually discards the device altogether, remarking that he's fed up with not knowing where he's going.
Shortly after this, the Fourth Doctor and Romana are projected outside the known universe and into a universe of negative coordinates, known as Exo-Space. The TARDIS lands on a planet called Alzerius, where they are joined by a young prodigy named Adric. It's in E-Space that the Doctor destroys the last of a race of giant Vampires who had once threatened all life in his universe. Eventually, the Doctor and his two companions find themselves in a white void with no coordinates, a sort of membrane between the two universes. A way out soon forms, but Romana and K-9 choose to remain behind to help free a race of enslaved creatures in E-Space.
The Doctor and Adric have only just made it back when they're asked to help the people of Traken from a creature known as "Melkur." On Traken, Adric and the Doctor are introduced to the aristocratic teen Nyssa of Traken. Both Nyssa and her father, Tremas, assist the Doctor in stopping Melkur, who is in fact revealed to be another TARDIS that is controlled by the Master. The Master is narrowly defeated, but manages to take over Tremas' body, thus giving himself a new incarnation.
The Doctor decides to travel to Earth to scan a real Police Box as part of a plan to repair the "Chameleon Circuit", the shape-changing mechanism in the TARDIS. However, the Doctor soon spots a mysterious ghostly figure looking at him in the distance. He eventually confronts the figure, who warns him of future dangers.
As the Doctor prepares to travel to the planet Logopolis to get the Chameleon Circuit fixed, Tegan Jovanka appears in the console room. The conduit between E-Space and our own universe is revealed to be a Charged Vacuum Emboitment created by the mathematicians of Logopolis as part of a system to allow the Universe to continue on past its point of heat death. Nyssa shows up, explaining that she was brought to Logopolis by the same figure that the Doctor encountered. Logopolis soon falls under the Master's control, but the stasis field he is generating ends up releasing Entropy and eroding matter throughout the universe, threatening to destroy the entire universe.
The Master agrees to help the Doctor stop the spread of Entropy by adapting the Pharos Project radio telescope on Earth so that they are able to reopen the CVEs. However, when the Master tries to take control of it, the Doctor runs out under the upturned radio dish to sever the cable linking the Master to the CVEs. The Master makes the dish start rotating so that the Doctor will fall to his death. Before he falls, he manages to tear out the cable, only to leave his companions watching as he clings to the cable. As his grip begins to slip, he sees visions of all the enemies he's faced over the years, then falls. Adric, Nyssa, and Tegan gather around the mortally wounded Doctor and call out his name. The Doctor begins seeing visions of all his companions and even the Brigadier calling his name.
He then looks up at the three of them and utters his last words: "It's the end — but the moment has been prepared for..." He then motions to the white-clad figure of the Watcher, who begins approaching the Doctor. The Watcher, a manifestation of the Doctor's future incarnation, merges with the Doctor and triggers his regeneration. "He was the Doctor all the time," remarks Nyssa, as the three watch him transform into the Fifth Doctor.
The Fourth Doctor appears again in the 20th anniversary special "The Five Doctors". A renegade Time Lord attempts to pull the first five incarnations of the Doctor out of time, inadvertently trapping the Fourth Doctor in a "time eddy" from which they are later freed. The Fourth Doctor also had a small cameo at the beginning of Dimensions in Time, warning his Third, Fifth, Sixth and Seventh incarnation to watch out for The Rani. Brief holographic clips of the Fourth Doctor appear in "The Next Doctor" and "The Eleventh Hour".
In the fiftieth anniversary special, "The Day of the Doctor", the Fourth Doctor appears again in clips as past and future incarnations come together to assist in the saving of Gallifrey. Tom Baker also appears in the final scene of the episode, as a mysterious elderly museum curator who appears right after the Eleventh Doctor remarks he would like to hold this job some day. He alludes to his resemblance to the Fourth Doctor by talking about revisiting "old favourite" faces and hints that he too might be or have been the Doctor.
The Fourth Doctor appeared in 172 episodes over a seven-year period, from 1974 to 1981. This makes him the longest-running on-screen Doctor of the series.
He also appeared in the specials "The Five Doctors", and made his final appearance as the Doctor in the charity special Dimensions in Time.