The Save the Tigers Sudoku series is a collection of Sudoku puzzles for all skill levels. Sudoku is the puzzle phenomenon from Japan that has now spread to the United States and beyond. You do not need to learn or use any math. By playing these special edition series puzzles, you can have hours of enjoyment while you help to save endangered tigers from extinction. This edition contains wickedly hard puzzles intended for advanced Sudoku players. Be sure to check out the other books in this series for even more fun