- 250 exciting puzzles - 50 EASY + 50 MEDIUM + 50 HARD and 100 VERY HARD LEVELS.- each Sudoku has a unique solution - tasks are conveniently located - large font - develops memory, logical thinking, helps to focus - 2 puzzles on the page - wide internal fields allow you to record your decisions and thoughts- very convenient and practical - expands creative possibilities - perfect gift for all fans of puzzles. An excellent book for free time pastime and mind training. I hope you enjoy my book. I would also be very grateful if you could write a review. Thank you. Best regards, Andrii Pitenko