The Visitor is a novel by the best-selling author Lee Child. The story follows Jack Reacher, a former member of the Army Military Police (MP), who finds himself embroiled in the middle of an FBI investigation. When former Army women start dying, the FBI brings in one of their top profilers, Julia Lamarr. Her profile describes Jack Reacher to a "T." Hence the FBI bribes Reacher, for the safety of his girlfriend, to act as a consultant in helping them find the murderer.

Twists and turns throughout the novel take the FBI agents and Reacher from one side of the country to the next. Reacher even calls in favors from his Army contacts to try to help himself get free from the grips of the FBI. While Reacher's original theory is just one to buy him some time, it turns out the killer and Reacher think quite alike.

The ultimate twist is at the end of the novel, when it turns out that hypnosis and one of its own is involved with the murders. Since the serial killer is dead and Reacher promises to keep it a secret that an FBI agent was a serial killer, Reacher is finally free to live the life he wants as a wanderer.