The next installment in the popular Jumbo Sudoku series, Jumbo Sudoku Ultimate Challenge includes over 300 puzzles. The popular numerical brainteaser is a fun way to work your brain, and Sudoku fans will love this collection. Jumbo Sudoku Ultimate Challenge includes classic Sudoku as well as-Samurai, Kakuro, Killer, Battleship and "Son of Sudoku" Futoshiki puzzles. All the puzzles are rated on a scale of tricky to fiendish, so if you are looking to finally be challenged by Sudoku, this is the book you have been waiting for!