Jack Reacher is a fictional character created by author Lee Child. He is a former military policeman who wanders the United States, often getting involved in dangerous situations. Reacher is known for his strong sense of justice, resourcefulness, and physical prowess, making him a formidable opponent to those who break the law. The character first appeared in the novel Killing Floor in 1997 and has since been featured in numerous books. Jack Reacher has also been adapted into films, with actors like Tom Cruise portraying him on screen. The series has gained a large following due to its thrilling plots and engaging storytelling.