Monster is a psychological thriller and murder mystery novel by Jonathan Kellerman. It is the fourteenth novel in the Alex Delaware series.

The mutilated body of an aspiring actor is found in the trunk of a car parked near an industrial area. Weeks later, another body appears in similar condition at another location. This time the body is a female psychology doctor who was working in a state facility for psychotic criminals. One similarity of the mutilations is obvious. The eyes were targeted. The case goes to LAPD detective Milo Sturgis, assisted by Dr. Alex Delaware, an old friend and psychological consultant.