When Isaac Asimov and George Scithers began planning Isaac Asimov’s Science Fiction Magazine (henceforth, IASFM) in 1976, George approached me at a gathering of the Trap Door Spiders, a curious club to which the three of us belong, to suggest a puzzle feature. Was it possible, he asked, to weave a puzzle into some sort of science fiction vignette or pastiche? In other words, present the puzzle with a SF story line. If so, would I be interested in doing this as a regular feature for the new magazine?

The idea was intriguing, especially since I had once perpetrated two SF stories based on topological curiosities: “The No-Sided Professor” and “The Island of Five Colors.” I cleaned up an off-color combinatorial problem, never before published , for my contribution to Volume 1, Number 1, dated Spring 1977, and have been writing the puzzles ever since. I enjoy writing them and I know from letters that readers like to work on them.

This book brings together the first thirty-six IASFM puzzles. To almost all of them I have added a postscript, which allows me to explain some (not all) of my compulsive wordplay, to thank whoever should be thanked, to discuss feedback from readers, and to suggest books and articles containing interesting material relating to the puzzles. Good puzzles are usually jumping-off points for serious mathematics. You’d be surprised how much math you can learn by exploring some of the implications and ramifications of what may seem at first no more than a trivial brainteaser.