William Hartnell
The mystery of the Doctor was introduced by William Hartnell, who played the first Doctor from September 1963 until October 1966. He was an elderly man with no name, a scientist who spoke of being an exile who traveled through time and space in a time machine he could barely control, which was stuck in the shape of a police box. The first Doctor was irritable, forgetful, rude, and sometimes untrustworthy. In An Unearthly Child, the Doctor willfully abducts Barbara Wright and Ian Chesterson, a pair of teachers who followed the Doctor's peculiar grandaughter Susan home from school, to stop them from going to the authorities after learing the truth about the TARDIS .In the following episode, The Daleks, he covertly sabotages the TARDIS as an excuse to explore outside the safety of the ship, putting everyone in danger. The first Doctor's character mellows in time, however: he was humanized by the people he knew and met on his travels.
Patrick Troughton
The Doctor, magically transformed, was younger with a new personality which in some ways set the stage for all later Doctors. This Doctor displayed considerable knowledge and expertise gained through extensive travels, and had even gained some small measure of control over the TARDIS although not much more than his predecessor. Troughton's Doctor also had a sense of wonder, coupled with a child-like playfulness. But while he often played the fool, capering with a disarming smile and playing his recorder, he hid the mind of a brilliant scientist. The second Doctor's first story, which no longer exists in the BBC archives, was The Power of the Daleks. The six-part story was broadcast between November and December of 1966. His last regular story was The War Games, broadcast in 1969. It was this ten-part story that revealed the Doctor's origins, which heretofore had only been hinted at: he was one of a race called the Timelords, who had mastery over time and space, but who were content to watch without interfering. The Doctor was taken back to his at the time unnamed home world, and put on trial for the crime of stealing a TARDIS and interfering in the universe outside. His sentence was a forced regeneration, and exile on Earth in the twentieth century, with the knowledge of how to operate the TARDIS blocked from his mind.
John Pertwee
The third Doctor made his debut in the January 1970 story Spearhead from Space. This was the first story to be shot in color. The third Doctor had the arrogance of Hartnell, experience equal to, or greater than Troughton, and an infusion of Jon Pertwee's own personality. The third Doctor spent all of season seven trapped in Earth's present, where he was assisted, and sometimes hindered by UNIT, the United Nations Intelligence Taskforce, lead by Brigadeer Lethbridge-Stewart. In the next two seasons, he occasionally left 20th-century Earth, but without control of the TARDIS, which was being operated remotely by a faction group of Timelords called the Celestial Intervention Agency. After the tenth anniversary story, The Three Doctors (1972-1973), his freedom was restored and he travelled again in time and space, returning frequently to twentieth-century Earth to help the Brigadeer.
