A Man of Affairs — John D. MacDonald

Sam Glidden owed all his success to the opportunities he'd received from Thomas McGann, president of the Harrison Corporation. But now McGann was dead, and Mike Dean, a wildly flamboyant business speculator, was looking to add the Harrison Corporation to his long list of conquests.

McGann's spoiled offspring, Tommy and Louise, saw the chance to make instant big bucks by selling out their shares. But Sam Glidden couldn't stand to see everything he'd worked for gobbled up by a barracuda like Mike Dean. So he wangled an invitation to the sand-and-surf soiree Dean planned for Louise and Tommy in the Bahamas ...