A Puzzle Book For Smart Adult: Enjoy the most popular puzzle game in the world! whether you want to keep your brain young and active, develop logical thinking or just keep yourself busy to avoid boredom... this book will help you with its unique Sudoku Puzzle. 100 Puzzles of 4 difficult levels 25 Puzzles - Easy Level. 25 Puzzles - Medium Level. 25 Puzzles - Hard Level. 25 Puzzles - Very Hard Level. 1 problems per page Solutions at the end of the book. Large size 8.5 x 11". Perfect gift for sudoku lover. Your brain will thank you!