The color of the cover gives it the appearance of a 7th or 8th edition, but my eye is completely untrained when it comes to books & literature. Be sure to post up what you find out from someone that knows books, it's a very nice find & at that price point it is definitely a bargain - what remains to be seen is just how good the bargain was. Congrats on the find & good eye for catching it, I can say with 100% certainty that I would have passed it by without a second glance but now you've educated me - LOL