The New York Times Will Shortz Presents Diabolical KenKen: 300 Logic Puzzles That Make You Smarter, Paperback/The New York Times

Get ready for the biggest, baddest KenKen puzzles yet from the New York Times This New York Times edition of KenKen contains 300 5x5 and 7x7 size puzzles with ``How to Solve`` instructions and an introduction by puzzlemaster Will Shortz. The puzzles use all four mathematical operations and increase in difficulty like they do in the Times.