I had the pleasure of taking the class based around this book from Christos Papadimitriou while at UC Berkeley. It is indeed a concise and excellent book. If you see it in person you'll be surprised how short it is compared to most textbooks. I must confess, though, that some of the exercises can be absolutely maddening.

Dead tree link for those interested: http://www.amazon.com/Algorithms-Sanjoy-Dasgupta/dp/00735234...