Those who solve even the most difficult puzzles seek ever higher challenges. However, there is a limit far above, and from that point on, guessing is the only option. But with these 500 Sudokus, you definitely won't have to resort to guessing – we promise! Over 30 different methods and techniques guide you along the logical path, no matter how arduous it may be. All the puzzles in this book have already undergone this journey and have been individually checked, tested, rated, and sorted by difficulty. Maximum puzzle fun at the edge of the possible!.