Dicks has written many novelizations of stories from the "Doctor Who" television series, including ones of shows that he did not originally write. In each he follows the original story line and tries to capture the personalities of the characters as portrayed on television.

When he wrote the script for The Five Doctors, he found that Tom Baker, the actor who had portrayed the fourth Doctor, would be unavailable, hence the device of having Doctor Four left in limbo. The original actor for the first Doctor was William Hartnell, an older man who portrayed his character as someone who was mysterious and arrogant. Hartnell began the show in 1963 but left in 1966 because he was suffering from multiple sclerosis. Hartnell died in 1975, and his part in The Five Doctors was taken by Richard Hurndall, who successfully captured Hartnell's voice and mannerisms.

Patrick Troughton portrayed a...