The Valentine Estate - Stanley Ellin

Edgar Award Finalist: A former Miami Beach tennis pro discovers the dangerous price of marrying for money in "one of the year's best chillers" (The New York Times Book Review).
There was a time when Davis Cup winner Chris Monte had it all. Now, down and out in Dade County, restringing racquets at a South Beach tennis shop and hiring himself out for an occasional lesson, he's dead broke. Then, along comes Elizabeth Jones, a mousy student with an irresistible proposition: fifty thousand dollars in exchange for marrying her. As sole beneficiary of the Valentine estate, Elizabeth is set to inherit a fortune. There's only one stipulation: She must be married. She'll collect, they'll divorce, and Chris will get paid off. Simple.
But there are a few details Elizabeth left out, including the other claimants who are ruthlessly scheming to get their shares; her former boss, a goon with shady connections; her institutionalized mother, the target of whispers and gossip; the syndicate representative behind the execution of the will; and the pressing question of the actual identity of the deceased. Before long, Chris is in over his head. And wondering what his real part is in this twisted game of family secrets, Chris has good reason to fear that in agreeing to marry Elizabeth, he's set in motion the carefully drawn plans for his own murder.
From a Mystery Writers of America Grand Master, The Valentine Estate is a gripping thriller and was named an Edgar Award finalist for Best Novel.