Open the Big Book of Brain Games anywhere and you'll find an amazing collection of 1,000 challenges, puzzles, riddles, optical illusions – originals and must-do classics (and it's pretty much guaranteed to make you smarter.) Each page is jampacked and features a full-color illustration for each entry. Twelve basic categories include Geometry, Patterns, Numbers, Logic and Probability, and Perception. An easy-to-read key at the top of each game ranks its difficulty on a scale of 1 to 10, while indices in the back cross-reference the puzzles. Softcover, 420 pages.