Book excerpt: Prepare to be obsessed. Match wits with the experts who created Sudoku. Arranged from “Easy” to “Very Hard,” here are over 300 logic puzzles that celebrate the compulsive joy of Sudoku with symmetry, smartness, and elegance—qualities lacking in computer-generated puzzles. It’s fiendish fun…every puzzle is designed by an author who anticipates your next step and obscurest the path, while never leading you into frustration.