Hi!
Thanks for buying
Manhattan GMAT books!
The 2005 editions are in fact 3 editions outdated. Since the 2005 editions, we have updated quite a bit. In fact, in our 2005 editions, I believe Critical Reasoning & Reading Comprehension were still just one book! We've added a lot of new content as well as strategies, including everything from weighted averages and quadratic equations to techniques for difficult language during reading comprehension and modifier exceptions in sentence correction. The books are, in fact, completely different.
While I am sure you could still get a lot of use out of the 2005 editions, the 4th editions are more comprehensive and offer a reflection of the test which is probably a little more accurate. If you chose to buy used editions, I would urge you to at least try and find copies of our 3rd edition.
If you are still on the fence, I would suggest visiting one of our centers or a Barnes & Noble and flipping through the 4th edition to see exactly what has changed.
If you have any further questions, please don't hesitate to give us a call at 1-800-576-4628.
Thanks!