Are you a Sudoku addict and searching for a new high? Help is at hand with Hitori, which can be thought of as a kind of "inverse" Sudoku. The intrepid player is presented with a grid in which every square contains a number. The aim of the game is to shade in squares so that no number appears twice in any one row or column--while making sure shaded squares never touch. What's more, unshaded squares must form a single continuous area, being in contact with another unshaded square on at least one side. This compulsive collection features more than 100 all-new puzzles of increasing difficulty. The book also contains a full introduction, player's guide, hints, tips, and solutions if you get really stuck. So if you think you've got Sudoku figured out, try Hitori--the gripping game that's so good, you'll be desperate for your daily fix. Gareth Moore's previous book was "The Book of Kakuro and How To Solve It."