Blue Moon is a novel by British writer Lee Child. This is the twenty-fourth book in the Jack Reacher series, and the last to be written by Lee Child alone Delacorte Publisher initially released the book on 29 October 2019.

Jack Reacher gets off a bus in an unnamed city east of the Mississippi after spotting a mugger trying to rob an elderly man. He foils the mugging, and the man introduces himself as Aaron Shevick. He reveals that the large bundle of cash he's carrying is intended for a loan shark named Fisnik who is associated with the local Albanian mafia, headed up by a mobster named Dino. Unbeknownst to both Reacher and Shevick, Fisnik is already dead, having been murdered on Dino's orders after Gregory, the boss of the rival Ukrainian mafia, framed him and another Albanian gangster as police informants.