It's a pocket-size brain gym. Here are more than 500 full-color puzzles from the original Big Book of Brain Games --the book that Will Shortz praised as "the most wide-ranging, visually appealing, entertaining collection of brainteasers since Sam Lloyd's Cyclopedia of Puzzles ," and The Washington Post called "an opus . . . mixing math with wonder." Here are mental games, visual challenges, logic posers, riddles, and illusions, each designed to stretch...