I can tell you outright that most of the Gouge files you'll find in this thread are significantly more helpful than books. However, there are some prep books recommended by title that are good, and I don't think it matters which version. The reason is that the ASTB isn't using "exact" answers or anything. The books just teach you how to think in the way necessary—
and at the speed necessary—to make it through the ASTB with proper pacing.
If I had to recommend
one source besides the gouge files (e.g., Marine gouge, Atrickpay's guide), I would recommend the ARCO book, which is—surprise!—posted in its entirety in this thread. Shell out a few bucks and go print that motherfucker at Kinko's, because it's the best source
aside from the gouge available to you for studying.
Based on your posts, I'm assuming your biggest concerns are the Reading Comprehension and Mechanical sections, so here's what I have to say about those:
- The Reading Comprehension section is all a matter of "method"—you need to purchase one of the recommended books in the thread and just do all the RC questions so you know how you're supposed to be thinking. The book I recommend is Officer Candidate Tests for Dummies, and I don't remember if it's one of the ones in this thread or not. That book will include reading comprehension problems along with a basic overview of the other stuff. I don't think this book prepared me that well for most of the other stuff, but if you've got time, it can't hurt.
- The Mechanical section is all a matter of "knowledge"—there are simply things you'll need to know, like pulleys, mechanical advantage, Newton's laws, gears, etc. I promise you that you will not find a better source of information than the combined gouge files posted on this forum (e.g., Marine gouge, Atrickpay's guide). You will find those files in this thread if you have not already. Some people have even expanded on those guides and combined them since I took the ASTB in July, so that's even easier.
WARNING: I went into the test fearing Math and Mechanical, and I left feeling the worst about Spatial Apperception and Aviation knowledge. If you need to brush up on your math, I highly recommend the
ARCO GRE/GMAT Math book, the one I purchased. You'll learn everything you need to know from the Gouge, but unless you're really good at math, running through all the relevant problems in the GRE Math book I linked will help you achieve the speed and comfort you need in order to ace that section. You'll also want to go through the FAA handbook (or whatever it's called) and just read that whole thing—once if you already have a comfortable knowledge of aviation and
twice if you don't.