Not in the Book is a comedy thriller play by the British writer Arthur Watkyn.

The original West End cast included Philip Guard, Avice Landone, Martin Wyldeck, Wilfrid Hyde-White, Sydney Tafler, Charles Heslop and Michael Nightingale.

[2] It subsequently went on tour with Jack Hulbert starring and was translated into several languages.

A respectable family man's life is thrown into jeopardy when he is approached by a shady South American who attempts to blackmail him about his misspent youth there.

He decides the only way to escape from his predicament is to murder the blackmailer, but things go wrong.