Active Brain Series Pocket Book 9 contains 200 sudoku puzzles in a compact size you can take everywhere with you. Sudoku is a fun way to exercise your brain and there are plenty of puzzles in this book to give it a really good workout! There are four levels of difficulty to take your playing to the next level, with 50 easy, 50 medium, 50 hard and 50 extra hard puzzles. The book is 8.5" high by 5.5" wide and has 2 puzzles per page. Solutions are printed at the end of the book.