While volume graphics have historically been in the realm of scientific visualization, modern GPU's make it possible to render gaseous phenomena such as clouds and fire using true volumetric data in games and simulators at high framerates. Using real-time ray casting to render these objects is quite feasible on modern GPU's, but it's an intimidating-sounding technique.
It really isn't, and this book helps to demystify volumetric rendering using 3D textures, GPU ray-casting, and other techniques. It really isn't hard to understand the concepts; this book presents the math behind it well without going overboard - it's all well-explained.
What's really valuable, however, is all the practical advice stashed in here. If you've experimented with real-time ray casting before, you've likely beaten your head against the wall fighting sampling artifacts, figuring out how to properly add procedural noise to the results, and squeezing enough performance out of your fragment program to not slow down the rest of your scene. If you got past all those hurdles, then you probably gave up when you had to figure out how to deal with intersections between your volume and the rest of your scene, or what to do when the camera goes inside the volume.
This book has chapters on all of those topics, and that's what makes this an invaluable reference for volume graphics that are part of bigger applications. Most of the other research and material on this subject assume you're rendering a single object in isolation, but in a game engine that isn't the case. This book bridges the gap between scientific visualization, games and other visual simulation applications, and finally makes these exciting techniques accessible to a whole new class of applications.
Once it all comes together, the results are truly amazing. You'll find yourself using volume graphics for all sorts of situations and adding an incredible air of reality to your applications as a result. Highly recommended!