The Little Book of Sudoku Volume Four Author:Gareth Moore Featuring varying difficulty levels, this compendium of exciting sudoku puzzles is perfect for both challenging experts and training novices. Not only fun, these puzzles are perfect for building logic and reasoning skills, improving memory, and keeping your brain healthy with a regular workout. Anyone's mind can be kept busy, but beware, as thou... more »sands of people have found, it's highly addictive!« less