Extra tricky. Extra tough. It's the sudoku collection that's not for the faint of heart.If you're craving the challenge, sharpen your pencil and pit your wits against the Japanese puzzle-makers at the top of their game.In each of these more than 300 handcrafted puzzles, ranked by difficulty from expert to x-treme to ultimate, every move is an adventure, a one-on-one challenge with a grandmaster who delights in elegance, symmetry, and building in the occasional roadblock.But keep going. You'll solve it eventually... you genius!Can't get enough? Look for: ·The Original Sudoku ·The Original Sudoku Book 2 ·More Original Sudoku ·X-treme Sudoku ·Expert Sudoku ·The Original Sudoku Page-a-Day Calendar