The Doctor (Doctor Who) footage. Tom Baker did reappear, but as "the Curator", an ambiguously different character who he was not credited for playing. A voice actor, John Guilor, recorded a line of audio impersonating the First Doctor, for which he was credited as "Voice Over Artist". In other multi-Doctor stories, the multiple actors are all credited as "The Doctor", the exception being "The Three Doctors" (1972–73), which credited William Hartnell, Patrick Troughton and Jon Pertwee as "Doctor Who" as the 1972 serial preceded the practice of crediting the character as "The Doctor". In "Human Nature" (2007), the plot involves the Tenth Doctor altering
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,