The setup of The Poisoned Chocolates Case is rightly very famous: a lady is killed when a box of chocolates given to her husband by another member of his gentlemen’s club — who himself received them unsolicited through the mail — turns out to have been laced with poison. The police, with no culprit in sight, allow six amateurs with a fascination for real life crimes to theorise and present their own solutions, each one appearing watertight until someone finds a flaw that brings the edifice down. For this conceit alone, and the genius way Berkeley uses his different sleuths to unpick the sparse and simple known facts, this book has passed into near-legend in detective fiction circles.
Writing a decent novel of detection is difficult enough, as evinced by the fact that the form virtually died out by the 1960s, so taking the classic detective story and turning into a pastiche of itself is even harder again — it has to be both a story of crime and detection and a cunning vehicle for transcending the tropes thereof while simultaneously wallowing in them. Leo Bruce did this near-perfectly in Case for Three Detectives (1936) and a great many luminaries of the form dipped their toe into such conceits with aspects of their books, plots, or characterisation, but for a full-length novel to take this on successfully is something of a challenge that it would be beyond the abilities of most mortals.
The Invisible Event 