"The grotesquely grinning corpse in the Devonshire shack had died horribly--with a dish of mushrooms at his side. It contained enough death-dealing muscarine to kill thirty people. Why would an expert on fungi feast on a large quantity of this particularly poisonous species? A clue to the brilliant murderer who had baffled the best minds in London, was hidden in a series of letters and documents that no one seemed to care about except the dead man's son."--Jacket.