Three Act Tragedy (Poirot), Paperback Book, By: Agatha Christie

At an apparently respectable dinner party, a vicar is the first to die. Thirteen guests arrived at dinner at the actor's house. It was to be a particularly unlucky evening for the mild-mannered Reverend Stephen Babbington, who choked on his cocktail, went into convulsions and died. But when his martini glass was sent for chemical analysis, there was no trace of poison just as Poirot had predicted. Even more troubling for the great detective, there was absolutely no motive.