well, this book delivers the latest game programming technology in a way that is understandable for everyone, even the beginners. it covers various topics like adaptive instanced tessellation, sub-surface scattering and sub-screen ambient and directional occlusion. the book also contains example shaders and other very useful material, which is also available from the internet, though one without experience wouldnt understand the examples without the book.
With 700+ pages it is definitely the most wanted book for advanced game programmers, even if we consider its fairly high price ~70$.