Usually I prefer mysteries where character, atmosphere, theme, and environment are more important than plot: exactly the kind that The Poisoned Chocolates Case makes fun of several times. But this whodunit is a marvel.

Six different amateurs come up with six different theories about a murder the police have been unable to solve. Each one is convincing enough. You say to yourself, "All right, they're making assumptions about human nature here, but no more than later and more literary writers like P.D. James or (in a completely different way) Patricia Cornwell." But it turns out those assumptions are not mere conventions. They're mistakes, and the next one in line explodes them and wheels out a different theory, only to be shown up in turn.

I knew all along who would turn out to have the correct theory. What that theory was, I have to admit, was a complete surprise. And the only way to know it's correct is that the murderer tacitly admitted it through action. In a way, I'd like to see a sequel in which the policeman, or the maid of one of the suspects, or the author Anthony Berkeley comes on the scene and disproves the solution. This is the kind of story that should never end.