You don't need to be a math whiz to enjoy a great sudoku puzzle! Sharpen your mind and have some fun with this great collection of sudokus, including over 540 challenges across four difficulty levels (Warm Up, Challenging, Tough, and the ultimate Samurai Sudoku!) A must-have for all Sudoku enthusiasts. | The Big Book of Sudoku Red by Parragon Books, Spiral Bound | Indigo Chapters