There is a little bit of confusion in Write on Wipe Off Sudoku. The one listed here appears to be a 35 page book and is not due to be released until April 1, 2006. What I just bought is published by the same company Top That! It has a different ISBN of 1-905359-90-X. It is also Write on-Wipe off but instead of being a book, it consists of 100 Puzzles printed on plastic cards, one puzzle on each side .The cards are 4X4 inches. There are also cards with the answers with 9 on each side. The cards are very substantial and on stock similar to regular playing cards. Also included is a wipe- out pen and small cloth that allows you to wipe out your numbers after finishing so that it can be used again. There is almost nothing included in the way of hints and methods for solving, but in this case is not really a problem, a lot of books are that way. All this is packaged up in a first class durable slip-case-box with a magnetic closing flap. Very well thought out and done! A puzzle can be done while still in the box through a cut out window or the puzzles can be removed, spread around to others or a couple can be slipped in your pocket and done on the bus, plane, beach, while your boss is busy or even while descending in your parachute, if you’re so inclined. The one thing I would strongly recommend is to restrain yourself from doing the while driving that would be a good way of putting another meaning to the idea of Wipe Out! The cards are well made and can be re-used multiple times. They are numbered so you can keep note of those you have done and the time needed to solve. Then compare with others or your own times when re-solving. If you’re the “Old Uncle Joe” who can never solve anything, don’t despair if someone gives you a set of these. You can always use them as coasters and be “right in there” with the latest craze. I have only one caution though, don’t lose the marker, it may be difficult to find one that wipes off and has a fine tip, possibly they have them at a stationery or art supply store. Overall, a well designed product and it would be welcomed by anyone who loves Sudoku. You can purchase this book at Amazon.