When the going gets tough, the tough solve sudoku! Based on the British WWII poster, Keep Calm and Carry On, this lighthearted collection is sure to make every clever puzzle fan smile. This book packs hours of solving into a portable paperback with a flashy, fun cover. So grab a pencil and enjoy 200 easy to hard puzzles! Features: 200 easy to hard Will Shortz sudoku puzzles; portable and perfect for solving on the go; and, edited by the No. 1 man in American crosswords, Will Shortz.