More than 500 conundrums, mind-benders, and mathematical teasers will help puzzle fans push their IQ levels to the maximum. Visualize this collection as a ladder into the stratosphere of intelligence: 20 levels of ascending difficulty each contain a variety of numerical and alphabetical questions that tease and stimulate the brain. Start from the beginning, with Level One, and work methodically through to the end. Think logically, rationally, and...