Feeling brainy? Prove it, with 100 of the toughest conundrums ever gathered, curated by an acclaimed puzzle-setter. Try this: place eight queens on a regular chess board so that none can attack any others--in other words, so that no vertical, horizontal, or diagonal line holds more than one queen. Can you do it? Created by the world's brightest minds, these baffling brainteasers from across the globe are the best the world has to offer. Inside, you'll find dilemmas that have puzzled the most intelligent humans of our age. Now it's your turn to solve them!