A keyboard player I use to play with had an expression. Every time we'd comment about how difficult the music we were trying to play was he'd say "Yeah, but when you can finaly play it, think how good you'll be!" That's how this book will make you feel.
The material here is all advanced. It's amazing to me that a Leo Kottke tune is the easiest one in the book. You'll need to spend some serious practice time on this book, but once you do you'll open up your technique to a lot of new areas. This really is a good thing, there's tons of books out there for beginning players, but not nearly as many for the advanced musician. It's nice to see high quality materials at the upper end of the skill levels as well.
The CD is excellent and is worth listening to on it's own. The 12 songs on the CD are the actual recordings off of the artist's original album. I like to let the CD play while I drive so I can get the feel of the tune memorized before I start to learn it.
The tunes themselves tend towards the bluegrass end of things, although Tony Rice's tune has very much a jazz feel to it (it is, in fact, a Wes Montgomery song) and Russ Barenburg's song is more "Adult Contemporary". Everything else is pretty much foot stompin' bluegrass. Any one of those songs would be a great choice in a guitar contest at a bluegrass festival. Even if you don't learn teh entire song you'll still pick up a lot of cool riffs that you can add to your own solos.
If you're looking for a challenge and you're ready to work then you'll get a lot out of this book. And once you can play one or two of these songs, "Think how good you'll be."