Gardner M. Aha! Insight

Scientific American, 1978. – 179 p.A variety of puzzles and riddles with simple, but not easily divined, solutions from Martin Gardner, former "Mathematical Games" columnist for Scientific American (back when it was still very intellectual). Each puzzle is accompanied by both a short, direct explanation and more in-depth discussion generalizing the particular insight to other relevant problems and, in some cases, offering more challenging questions of the same form. Topics range from straight-up mathematics—arithmetic, geometry and number theory—to logic and even word games. These conundrums—and just as much, the abstract, seemingly childish yet sophisticated illustrations—delighted me as a child, though I was a bit young to appreciate their beauty and usefulness.