Caveman's Valentine by George Dawes Green features Romulus Ledbetter (Rom). Who at one time was a loving spouse and father until he went insane. Rom now lives in a cave in Upper Manhattan's Inwood Park. He grocery shops in garbage cans and alleys. Rom is so gone he believes in an evil presence, Cornelius Gould Stuyvesant, who is responsible for destroying mankind with the evil Y and Z rays. When he discovers a dead body of young man outside of his cave he knows that Stuyvesant has something to do with it. He must keep it together to find out who killed this man and why. This is a difficult book to read as Rom goes back and forth between reality and his reality. But a very satisifing read.

This book has been made into a movie in 2001 which stared Samuel L. Jackson.