This is the penultimate the "Black Widower" collection, and I must confess that it has not made much of an impression on me. None of the stories contained plots that I remembered before skimming the book after my first reading, although I definitely remembered them each as I did the skimming.

Here we have twelve stories which, as always, are very cerebral puzzles (the book’s title is very apt). I note that some turn on very trivial points indeed (the first two being what English word has four homonyms? and which element has a unique name?). The focus of a typical Black Widower story being the puzzle and not the people, that means that the puzzle carries most of the weight for the success (or failure) of the tale. Alas, but the the problems here are simply not as good as the problems in some of the other collections, and the result is a fairly weak anthology.