No need to stop the puzzle fun with Big Book of Sudoku Volume I! Sharpen your mind and practice deductive reasoning with this second volume of sudoku puzzles for adults, including more than 540 challenges across four difficulty levels: Warm-Up, Challenging, and Tough. When you are done, test your skills on the ultimate Samurai Sudoku Puzzle--5 puzzles linked together by one central puzzle! Can you become a master samurai? Challenge accepted! OVER 500 PUZZLES & SOLUTIONS: Hours of fun and entertainment to enjoy VARIETY OF LEVELS: From levels 1 to 3 increasing levels of difficulty, including beginner, medium, and hard LAY FLAT: Spiral-bound and paperback lays flat for ease of use at home or on the go MAKES A GREAT GIFT: For the sudoku puzzle lover, these books make great gifts for any birthdays, stocking suffers, road trips, and more PARRAGON PUZZLE BOOK COLLECTION: Look for additional adult puzzle books and sudoku books for adults from Parragon for all types of puzzles including crosswords, word searches, and more