A puzzle can only be solved once, making puzzle books perhaps the most disposable of all books. That's why the Puzzle Society created <I>The Green Book of Sudoku 2</I>.<P>With its aqueous (water-based) coating and biodegradable soy inks printed on recycled paper, this eco-friendly book wraps challenging and enjoyable puzzles in a disposable package that minimizes its effect on our environment.<P>Featuring 200 all-new Sudoku puzzles, <I>The Green Book of Sudoku 2</I> will keep your brain sharp while you help keep the environment healthy.