A new collection of previously unpublished Fiendish Su Doku puzzles Perfect for the advanced solver in need of a constant supply of ultra-difficult challenges, the puzzles in this collection are of the highest quality, guaranteed to provide hours of absorbing, brain-stretching entertainment. Each puzzle has a unique solution—and there's no guesswork required. You don’t need to be a mathematical genius to solve the treacherous puzzles in this eighth collection of Fiendishly difficult puzzles—it’s simply a question of logic.