The Doctor (Doctor Who) Time Lords a fixed number of twelve regenerations, meaning that every Time Lord had a total of thirteen incarnations including the original. The plot of "The Time of the Doctor" involves the Doctor receiving a new cycle of regenerations from the Time Lords before his expected demise, triggering the regeneration into the Twelfth Doctor, played by Peter Capaldi. The origins of the programme were explored in the docudrama "An Adventure in Space and Time" as part of the 50th anniversary celebrations of "Doctor Who", which starred David Bradley as William Hartnell. Although Time Lords resemble humans, their physiology differs in
Doctor Who in Canada and the United States CBC did not renew the program and it would not reappear on the network for 40 years. The BBC series was originally sold to television stations in the United States in 1972, with Time-Life Television syndicating selected episodes of Jon Pertwee's time as the Doctor. The series did not do well, despite an interesting write-up some years earlier in "TV Guide". Apparently, program directors of the commercial television stations that picked up the Jon Pertwee series did not know that the program was an episodic serial, and so it was constantly being shuffled about in the programming schedules. In 1978,