Diabolical Sudoku Super Challenger in Bloomington, MN

Yes, you read it right. The Sudoku puzzles in this book are diabolical because they're very difficult. You will have to spend some time to figure out the patterns and identify what numbers fit the grids. But the time you spend solving the puzzles will never go to waste because you're preparing yourself to become a much more effective problem solver. Grab a copy today.