When studying for the GMAT, most students correctly purchase the Official Guide to the GMAT from GMAC.org as their first test prep book. Whether to use a private tutor vs. a group class or go it alone is a decision we address throughout this site.
However, when it comes to choosing what supplementary materials to use, beyond the Offical Guide, there are a number of excellent "boutique" options out there. For students looking for loads of real practice with concepts broken down clearly and concisely, we recommend GMAT Hacks below: