From the Edgar Award-winning author of the Peter Duluth Mysteries comes an electrifying thriller of one man's desperate search for his missing wife.   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 Venezuela, mining engineer Mark Liddon is hoping to surprise his wife as much as she surprised him by agreeing to marry him. After all, he came up the rough way in back rooms and boxing rings, while Ellie is a social scion from a family of money and influence.   But when Mark crosses the doorstep, Ellie is nowhere to be found and her ex-boyfriend is in their home, shot dead. Using instincts honed from a lifetime of hard knocks, Mark launches himself into an investigation of his own to find Ellie. But the further he goes in his search, the more people try to slow him down.   And now they're trying to kill him . . .