Triple Jeopardy — Rex Stout

The incredibly brilliant Nerd Wolfe is the orchid-growing gourmet whose sheer genius at deduction is without peer. Together with his confidential assistant, Archie Goodwin, he must draw; upon all his enormous talent and versatility to solve three separate cases with only three clues--a vitamin spiked with venom, a newspaper no one has read, and a monkey on its deathbed.