Jack Reacher is the protagonist of a series of crime thriller novels by British author Lee Child, a 2012 film adaptation, its 2016 sequel, and a television series on Amazon Prime Video. In the stories, Jack Reacher was a major in the US Army's military police. After leaving the army, Reacher roamed the United States, taking odd jobs investigating suspicious and dangerous situations.

James Dover Grant, primarily known by his pen name Lee Child, is a British author who writes thriller novels, and is best known for his Jack Reacher novel series. The books follow the adventures of a former American military policeman, Jack Reacher, who wanders the United States. His first novel, Killing Floor (1997), won both the Anthony Award and the 1998 Barry Award for Best First Novel.