I wouldn't bother buying the Costanzo textbook. The required book list has changed, and Guyton is the only required textbook now. Nothing that's in Costanzo isn't in Guyton and the new physiology professor (he teaches about half the course material) bases his powerpoints off of Guyton. A lot of people are terrified of the Guyton textbook, but the new professor only assigns certain pages out of it. Also, Costanzo has written the BRS Physiology book, so I would recommend you buy that instead. It's very easy to read, clear, and summarizes the important points nicely.