In this mystery from an Edgar Award-winning author, sleuth Peter Duluth must overcome his own demons as he investigates a case south of the border (Kirkus Reviews).   Patrick Quentin, best known for the Peter Duluth puzzle mysteries, also penned outstanding detective novels from the 1930s through the 1960s under other pseudonyms, including Q. Patrick and Jonathan Stagge. Anthony Boucher wrote: "Quentin is particularly noted for the enviable polish and grace which make him one of the leading American fabricants of the murderous comedy of manners; but this surface smoothness conceals intricate and meticulous plot construction as faultless as that of Agatha Christie."   Returning from World War II, Broadway big shot Peter Duluth thought he and his wife, Iris, could simply resume the life they had before. He was wrong. Peter is carrying some heavy baggage from his time in the service, and the weight is more than Iris can bear.   By the time the detective gets back to his old self, Iris is gone. Following his wife to Mexico, he discovers she's fallen for someone else. But Peter isn't about to give up and go home. He's going to stay and fight for her.   To win this battle, Peter will have to investigate the murder of Iris's lover's wife, become entangled with the man's depraved family--and face the possibility that the love of his life may a cold-blooded killer . . .