AP preparation books/guides?

Hello to all,</p>

I am new to this… Could anyone advise me which book/preparation guide is the best one for:</p>

– AP Environmental Science and
– AP Psychology</p>

I mean, considering I’ll be taking them this year (2014), which version of those books I would need to purchase?</p>

This post may sound silly, but this testing stuff is very new to me. I am from Europe, and we have different tests; unfortunately, if I ever decide to study in USA I would terribly need these tests as part of the entrance requirements.</p>

Thank you good people!</p>