This book features the following: - 100 puzzle grids- Easy, Medium, Hard and Very Hard level puzzles- Large grids and print font for prevention of eye-strain- History of Sudoku- Keep Your Mind Sharp With Sudoku- Sudoku Rules of Play- The Basic Rules of Sudoku- Answers (all solutions)25 Easy Difficulty Puzzles25 Medium Difficulty Puzzles25 Hard Difficulty Puzzles25 Very Hard Difficulty Puzzles Did you know the American Alzheimer's Association has endorsedSudoku as a "brain game" that might help to reduce risk ofdementia as we get older?