Extreme Sudoku: A collection of 200 of the toughest Sudoku puzzles known to man. (With their solutions.)

This book contains a selection of 200 of the hardest and most difficult Sudoku puzzles along with their solutions. These puzzles were selected among 17-clues Sudoku puzzles for their especially challenging nature and will provide hours of enjoyment and ample opportunity to practice the most advanced Sudoku resolution techniques.