Back cover copy, mostly! Though lately I've been mostly reading on my Kindle, which has really changed my buying habits. Now, I'm more likely to head to Amazon, browse the latest YA releases, and download a sample chapter from a half-dozen at a time (choosing from the blurbs that interest me). If I'm enjoying the sample chapter, I buy the book; if I'm not interested after reading the sample, then I don't. Interestingly enough, since I started reading/buying on my Kindle, I'd say I buy/read two to three times more books than I did before. The Kindle (and similar e-readers) are *very* dangerous for impulse buyers like me who suddenly find themselves with nothing to read at 10 p.m. at night.