Flex your brain power like never before!
From acclaimed author Dr. Gary Gruber, whose proven critical-thinking methods have sold more than seven million books, this collection of mind-bending brain teasers is sure to challenge even the most experienced problem solver. Inside are logic puzzles, riddles, maddening math problems, mental games, and more.
Dr. Gruber reveals the fascinating explanations and detailed strategies for solving even the trickiest problems using his exclusive Gruber Method.