GMAT during college or after? Whats a good GMAT prep book?

<p>Evening. </p>

<p>Quick Bio:
I'm currently a Sophomore at Saint Anselm College in Manchester, NH.
Major: Politics (BA) Minor: Economics </p>

<p>What I plan to do is take the GMAT during either my Junior year or summer semester to see how I do. If I do well, I plan on applying to Business school out of college. If I do not do well, I will apply later after graduation. Is this a good idea? </p>

<p>Anywho, I want to start studying after winter break, just so I can start to familiarize with the question format and whatnot. Does anyone know of a single book that would serve my purposes? </p>

<p>Appreciate it!</p>