Carol Vorderman, the UK's best-known mathematician and bestselling author of How To Do Sudoku and Carol Vorderman's Massive Book of Sudoku, returns once again with the perfect book for all those Sudoku addicts champing at the bit to take their skills to the next stage. In theory, Sudoku is a simple puzzle, but taken to a higher level, it can be teeth-grindingly infuriating. With the clear, step-by-step instructions, and start-to-finish examples that made her previous books such a success, Carol shows you how to acquire the skills you need to tackle the toughest Sudoku. And once you're ready to flex your new Sudoku muscles, 300 brand-new, hand-crafted puzzles await you: from regular Sudoku puzzles ratcheted up to severest of difficulty levels to new favourites such as Killer Sudoku, Squiffy Sudoku and Sudoku 16.You may be a Sudoku Master, but will you be able to master Extreme Sudoku?