Warning: danger ahead! These treacherously tough puzzles all require upper-level solving techniques to conquer. So, if you want hard sudoku that's easy to take on the go, this Sit & Solve® collection is the ticket. Attractively packaged, it's a terrific gift or stocking stuffer for hardcore sudoku fans.
About the Author
Frank Longo has had more than 3,000 crossword puzzles published since 1993, and in the past few years has turned his attention to the sudoku craze. He has published over 100 sudoku books, including Oy Vey! Sudoku; 10x10 Sudoku; Absolutely Nasty Sudoku Level 1, 2, 3, and 4; The World's Longest Sudoku Puzzle; The Sudoku Code (coauthored with Francis Heaney); and The Puzzlewright Guide to Solving Sudoku (coauthored with Peter Gordon).