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. OVER 500 PUZZLES & SOLUTIONS: Hours of fun and entertainment to enjoy! VARIETY OF LEVELS: From levels 1 to 3 increasing levels of difficulty including Warm Up, Challenging and Tough. When you are done, test your skills on the ultimate Samurai Sudoku Puzzle - 5 puzzles linked together by a central puzzle! Can you become a master samurai? LAY FLAT: Spiral-bound lays flat for ease of use at home or on the go. Whether your drinking your morning coffee, riding on the train or relaxing on vacation this sudoku book can go with you. MAKES A GREAT GIFT: For the sudoku puzzle lover, this books makes a great gift for any occasion! Birthday, stocking suffers, road trip or more, everyone will love it! PARRAGON PUZZLE BOOK COLLECTION: Look for additional puzzle books from Parragon for all types of puzzles including crosswords, word searches, and more!