This Sudoku book is packed with the following features: - 1000 Jigsaw Sudoku Puzzles from Easy to Hard (333 Easy - 334 Medium - 333 Hard).- Each puzzle is guaranteed to have only one solution.- Includes free bonus puzzles you can download book (Fitness for your brain: Word Search With Hidden Message: Train your brain anywhere, anytime! - 102 Puzzles for Adults and Seniors) - Answers to every puzzle are provided at the back of the book.- Six puzzles per page (8.5 x 11 inches). Playing Jigsaw Sudoku is not just a fun way to pass the time, due to its logical elements it has been found as a proven method of exercising and stimulating portions of your brain, training it even, if you will and just like training any other muscle regularly you can expect to see an improvement in cognitive functions. Some studies go as far as indicating regular puzzles can even help reduce the risk of Alzheimer's and other health problems in later life.Completing Jigsaw Sudoku regularly helps the brain process both problem solving and improves logical thought process with the use of deductive reasoning, which can also be applied to approaching real life challenges in a different manner.We hope this will be an entertaining and uplifting mental workout, enjoy Big Book of Jigsaw Sudoku.