Tripwire

Tripwire is the third book in the Jack Reacher series written by Lee Child. It was published in 1999 by Putnam in the United States and Bantam in the United Kingdom, and it is written in the third person.

The plot brings Reacher into a mystery involving a Vietnam War veteran who was reported missing in action and has resurfaced as a violent moneylender with a secret he is willing to kill to protect. The prologue describes the escape route that man, Victor Truman Hobie, has prepared in case anyone discovers his secret, and the early-warning system he calls his tripwires, which is where the title comes from. Reacher is lying low in Key West, digging swimming pools by hand, when a private detective starts asking questions about him.

Reacher's position in the series is stated on the jacket: a man who has no family, possessions or commitments, and who therefore cannot be found through the usual channels. That is why a private detective's inquiries are treated as a warning rather than an ordinary nuisance, and why the geography of the book moves from Florida to New York as the search proceeds.