Donald Bengtsson Hamilton (March 24, 1916 – November 20, 2006) was an American writer of novels, short stories, and non-fiction about the outdoors. His novels consist mostly of paperback originals, principally spy fiction, but also crime fiction and westerns, such as The Big Country. He is best known for his long-running Matt Helm series (1960-1993), which chronicles the adventures of an undercover counter-agent/assassin working for a secret American government agency.