Only You Can Save Mankind (1992) is the first novel in the Johnny Maxwell trilogy of children's books and fifth young adult novel by Terry Pratchett, author of the Discworld sequence of books. The following novels in the Johnny Maxwell Trilogy are Johnny and the Dead (1993) and Johnny and the Bomb (1996). The setting of the novels in the modern world was a departure for Pratchett, who wrote more regularly in fantasy world settings.

Johnny and the Bomb is a 1996 novel by Terry Pratchett. It is the third novel to feature Johnny Maxwell and his friends, and deals with the rules and consequences of time travel. The first two novels in the Johnny Maxwell Trilogy are Only You Can Save Mankind (1992) and Johnny and the Dead (1993).