Einstein's Riddle: Riddles, Paradoxes, and Conundrums to Stretch Your Mind
Challenging Logic Puzzles (Official Mensa Puzzle Book)
Sam Loyd's Cyclopedia of 5000 Puzzles tricks and Conundrums with Answers
The Colossal Book of Short Puzzles and Problems
The Moscow Puzzles: 359 Mathematical Recreations (Dover Recreational Math)
Are You Smart, or What? A Bizarre Book of Games & Fun for Everyone
Match Wits With Mensa: The Complete Quiz Book