Sudoku is a fun game which helps exercise the brain and also gives you a great sense of accomplishment. It is said that it can delay dementia by making your brain work in a different way. This book contains the biggest ever 9 by 9 grid Sudoku puzzles. The gigantic sized puzzle uses the whole letter size page leaving tons of room for penciling in the possibilities. There are 200 puzzles, 100 hard and 100 extra hard, one puzzle per page and solutions at the end of the book. 8.5" X 11"