<p>For US History, AMSCO is enough for an 800. If you want a review book that is more concise and focuses more on main ideas, I would buy the REA AP US History Crash Course book. I used both and looked through the entire AMSCO book the week before the test and got a 790.</p>
<p>For bio, if you want something in addition to Barron’s (which I think would suffice on its own), I would get Cliffnotes AP Biology. It’s designed for the AP exam and is much more detailed so I don’t think it’s necessary. But go ahead and buy it if you think it would help.</p>