Collected over several years by Peter Winkler, of Bell Labs, dozens of
elegant, intriguing challenges are presented in Mathematical Puzzles.
The answers are easy to explain, but without this book, devilishly hard
to find. Creative reasoning is the key to these puzzles. No involved
computation or higher mathematics is necessary, but your ability to
construct a mathematical proof will be severly tested--even if you are a
professional mathematician. For the truly adventurous, there is even a
chapter on unsolved puzzles.