Walter Wager was best known as an author of mystery and spy fiction; his works included 58 Minutes (1987), whose story was used as the basis of the action film Die Hard 2 in 1990. Two of his other novels became major motion pictures in 1977: Viper Three (1972), which was released as Twilight's Last Gleaming, and Telefon (1975). Wager wrote a number of original novels in the 1960s under the pseudonym "John Tiger" that were based on the TV series I Spy and Mission: Impossible.