1963: At 6:15 on a cold, wet night, the BBC premieres its new family science fiction show, Doctor Who, with its first episode, “An Unearthly Child.” The series will become a legendary part of modern British folklore and the longest-running sci-fi series on TV.

Featuring a benevolent traveling alien known only as The Doctor, the series followed the adventures of the heroic Time Lord and his human companions through time and space.

Originally developed by Canadian Sydney Newman, BBC’s head of drama, the day-to-day creation of the show’s first season fell to script department head Donald Wilson, BB...