If you’re already getting antsy to buy your textbooks (Amazon.com did just send out an email with some textbook promotions, after all) you can find out what books you’ll need pretty easily.
Just check out the bookstore online! This link should bring you right to the main page: http://www.bkstr.com/Home/10001-10370-1?demoKey=s. Alternatively, you can seek the wisdom of the oracle (read: Google “gwu book store”).
Just enter in the information for your course in the books section and the site will tell you what’s been listed with them. The list is up to the professor for your course, so nothing will be listed if the professor hasn’t listed anything. Some professors don’t list anything at the bookstore because they make arrangements with independent bookstores (Prof. Winstead prefers this method), other professors simply haven’t listed anything yet.
If your books aren’t listed for your section, you can email the professor directly to ask them about it. Use the directory at my.gwu.edu to look up their email address.