The Guardian Killer Sudoku 2: A collection of more than 200 formidable puzzles (Guardian Puzzle Books)

Test your wits against 210 brand-new killer sudokus with this formidable collection of the world's favourite puzzle. This compilation draws on all the knowledge of the expert puzzle writers at the Guardian, whose killer sudokus are enjoyed by hundreds of thousands of people every day. All of your logical reasoning will be required to solve these previously unpublished puzzles, specially designed to increase in difficulty as the book progresses.