<p> The Official Utterly Addictive Number-Placing Puzzle </p> <p> Will solving the Difficult Su Doku puzzles in this sensational collection be the death of you? There?s only one way to find out. More than just hours of entertainment, Su Doku engages your mind, improves your concentration, and helps you stay mentally fit. With 150 brand-new puzzles to complete, you?ll become a Su Doku master in no time! </p>