Doctor Who is the longest-running and most successful science fiction program in history. Debuting in 1963, the BBC series ran for an unprecedented 26 years, only to come back for a new generation in 2005. The story concerns the Doctor, a Time Lord who travels through space and time, using a machine called the TARDIS to explore strange worlds, learn about the universe and do some good along the way. Due to the unusually long run of Doctor Who, the role of the Doctor has been played by eleven different actors, each one representing a "regeneration" through which the Doctor acquires a new body and even a few new personality quirks.
Cast
William Hartnell was the first man to play The Doctor, starring in the original series run for three years.
Patrick Troughton carried the role for three more years after Hartnell closed the door on the TARDIS for the last time.
Jon Pertwee was the first Doctor of the 1970's, maintaining the role until 1974.
Tom Baker took over for Pertwee and played the Doctor longer than anyone else, his seven-year tenure ending in 1981.
Peter Davison and Colin Baker starred as the Doctor, respectively, until 1984 and 1986.
Sylvester McCoy was the final Doctor of the original series. He reprised the role for the one-off 1996 Doctor Who television movie, which featured Paul McGann's only on-screen appearance as the Doctor.
Christopher Eccleston was the first new Doctor of the official 2005 revival, though he left the series after one season.
David Tennant is today's most familiar face for the Doctor. He played the iconic role for five seasons.
Matt Smith is the newest Doctor. He premiered in 2010 and has signed on to star for at least two seasons. He is, to date, the youngest actor to ever portray the Doctor.
Karen Gillan plays Amy Pond, the Doctor's current companion.
Arthur Darville is Rory Williams, Amy's husband and fellow companion.
Doctor Who's enduring popularity and success has led to many spin-off shows, the most successful being Torchwood (starring Doctor Who co-star John Barrowman) and The Sarah Jane Adventures (featuring the late Elisabeth Sladen, reprising her character from the classic series of Doctor Who).