Put your brain through it's paces with this great value Brain Gym book of 1500 Very Hard Sudoku puzzles, perfect for the advanced Sudoku solver, or anyone who wants to have tons of puzzles to keep them busy. With only 4 puzzles per page there is plenty of room for small notations. We exercise our bodies but our brains need a workout too! Sudoku helps keep your brain healthy and functioning well. Challenge yourself to finish all the puzzles without cheating! Solutions to all the puzzles are at the end of the book. 506 pages, 4 puzzles per page. 8.5 by 11".