In this "fun" mystery from an Edgar Award-winning author, amateur sleuth Peter Duluth learns that divorce can be murder (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."   On extended shore leave from the war in the Pacific, navy lieutenant Peter Duluth and his movie star wife, Iris, have escaped from the prying eyes of the press, landing at the Nevada desert mansion of their friend Lorraine Playgel. Unfortunately, they aren't alone.   Staying with Lorraine are three old school friends who are all waiting to get a Reno divorce from their respective husbands for very different reasons. But the brassy Lorraine can't help but stir up some drama by inviting all three soon-to-be exes out to the oasis. Naturally, things are a bit uncomfortable at first.   Then the tension snaps with lethal results. One of the hopeful divorcées turns up dead, followed quickly by another. Knowing there must be a lot more than just alimony at stake, Peter and Iris start hunting for a killer who's taking "till death do we part" quite literally . . .