My favorite type of story is one that deals with a character who is a fish out of water, so to speak. Think of Babe Levy in William Goldman’s MARATHON MAN, for example. Right behind that would be the crab-in-a-barrel story: the crustacean that is smarter than his buds figures out how to crawl up the side of the barrel to go up and over, only to be dragged back down into the world it knows.

THINK OF A NUMBER by John Verdon is closer to the latter type of story, with Dave Gurney starring as the crab. Gurney, newly retired from his position as the NYPD’s top homicide investigator, has moved out of the city with his wife Madeleine and into a farmhouse near the village of Walnut Crossing. He is one of those crabs, in other words, who has actually made it out of the barrel. Unconsciously or otherwise, however, Gurney wants to be dragged back in. He spends his days as a Photoshop artiste, manipulating mug shots of serial murderers into works of art that have acquired a paying audience thanks to the subject matter, his eye for the unusual, and his own notoriety, acquired through his resolution of high-profile cases.

It’s a telephone call from a gone and almost forgotten acquaintance that ultimately brings Gurney back into the hunt. Mark Mellery is the acquaintance, a scholar of the hale-fellow-well-met sciences who is 250 pounds of manure in a 100-pound bag. Mellery has done quite well for himself with a New Age-type retreat and counseling center that has enabled him to become a member in good standing of the rich and famous. His world has been rocked to its core, though, with his receipt of a series of mysterious letters written in verse indicating that the sender 1) knows him very well, and 2) wishes him ill will. Mellery is particularly unsettled when a letter asks him to think of a number; a second one enclosed with the first correctly notes the number Mellery had in mind. Gurney is intrigued but initially reluctant to get involved, suggesting instead that Mellery contact the police. Mellery refuses, and Gurney, his wife’s misgivings notwithstanding, gets tugged back into the barrel. More letters follow, including another that demonstrates the sender’s ability to read Mellery’s mind.

Everything changes, however, when Mellery is brutally murdered. Gurney is brought in as a special investigator, in part because of his initial involvement with Mellery and also because the few clues left at the scene of the crime are contradictory and confusing. Gurney is at loose ends. Nothing makes sense. And even when other murders are discovered, and Gurney is able to determine what is going on, he is no closer to discovering the “who” or the “why” of the killings.

A first-class mystery? You bet, although students of the genre will no doubt deduce one or more of the puzzles before the book’s halfway point. But this is also the story of the unraveling of Gurney’s marriage --- slowly, quietly, inexorably --- a process of which he is aware but either is unable or unwilling to stand athwart and yell halt. His retirement domesticity does not sit well with him, the result being that he neglects his house and family so that both are crumbling around him. There are times when one wants to reach into the pages and shake Gurney --- a likable enough guy, all things considered --- to remind him to do this or that. The resolution of one problem leads indirectly to that of another, though that does not necessarily mean all will be well. As we approach the end of the novel, Gurney has a sense of what is truly important to him. By then, unfortunately, it may be too late.

If there is a problem with THINK OF A NUMBER, it’s that it seems to contain almost too many great ideas, as if Verdon wanted to explore a vast number of issues and characters and had only one book within which to do so. Those who survive the ending will embrace a second round, and Verdon just may get that chance, given the novel’s popular reception. If there is any justice in the world, he will.