Get your brain active with this Active Brain Series 2 book containing 1,000 extra hard Sudoku puzzles with solutions, perfect for the Sudoku enthusiast. With only one level of difficulty there are no wasted puzzles. 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 The book is 8.5" by 11" and has 4 puzzles per page with room for notes.