ou know how hard it is to find good ones. Thankfully, the folks at mental_floss--the popular trivia magazine--have come to the rescue with a topnotch book of 72 puzzles that will flex your logical reasoning to the max. Each puzzle comes with a grid to mark your deductions, so put on your thinking cap and start solving. And dont worry if you have to erase your answers; the high-quality paper wont rip!