Where There's a Will by Rex Stout

Millionaire Noel Hawthorne has just died in a hunting accident. In his will, he leaves his sisters (named April, May, and June) a peach, a pear, and an apple, respectively. But, to a young woman who was _not_ his wife, he leaves a huge chunk of his fortune. The sisters come to Wolfe to find out what's behind this wacky will. But Wolfe suspects that maybe the hunting accident was no accident...