The Must Have Sudoku Puzzle book is a fresh new collection of 300+ Sudoku puzzles for the leap year. This Book Contains 300+ Hard Sudoku Puzzles for beginners and experienced Sudoku Puzzlers. Improves your memory. Memory and logic work side-by-side when you are playing Sudoku Stimulates your mind keeping your brain active Learns to do things quickly Increases your concentration power. Feel Happy .