Brief edition vs "real" edition

<p>I am taking a college english class concurrently at my high school. I accidentally bought the brief edition off of amazon rather than the real edition. I needed the 3rd edition and my textbook that I got is a 3rd brief edition. It is missing the last three chapters and seems to have the rest of the material. I was wondering if anyone could help me out because I am curious to know if there may be anymore missing material. The book is Writing: A Guide for College and Beyond Brief 3rd edition vs the regular 3rd edition.</p>