Straight Sudoku

This handy 5" x 8" book is full of over 200+ classic sudoku puzzles. There are easy, medium, hard, and extra hard sudoku puzzles in gradually increasing intensity. There is one sudoku puzzle per page. Each puzzle has only solution which can be found in the back of the book in the answers section. Keep this book on your person or within easy reach for those lucrative times when you have a couple minutes to yourself and want a mental challenge.