Who Killed Nobody Somehow?

Author Graham Tree is poisoned at a party celebrating the publication of his new book. Tree miraculously survives and now it is Burke's job to find the killer before there is a second - successful - attempt on Tree's life. But Tree refuses to talk. His books, however, have created several notable enemies. Burke, in disguise, tricks the victim into revealing information that leads him to the killer. Was it the playboy, the polo player, the ruined oil man, Tree's publisher, or his socialite former flame? The would-be killer strikes again - will Burke get there in time?