The Guardian Killer Sudoku 1 : A collection of more than 200 challenging puzzles - The Guardian

The Guardian's killer Sudoku puzzles are enjoyed by hundreds of thousands of people every day. Now is your chance to try to solve 200 difficult previously unpublished killer Sudoku in the first book in the new Guardian puzzle book series. With only a minimal level of mathematical knowledge needed, but variety of difficulty levels, from easy to fiendish, this book can be enjoyed by both the killer Sudoku novice and the puzzle master with years of solving experience.