I'm not sure what I was expecting here, but this book wasn't really it.
Chapter One provides 32 pages of rules and guidelines for creating villains, including villanous archetypes, plots, and schemes. It also provides the obligatory score of new feats (such as Evil Brand, which provides bonuses to negotiations with evil creatures, or Mask of Gentility, which makes it harder for the PCs to read the villain's true intent) and some new spells (such as Alibi, which plants a false memory of the villain, or Friendly Fire, which lets the caster redirect an incoming ranged attack). There were some interesting tidbits in this section, but nothing that really triggered an "Aha!" moment. I felt that a lot of this material was just filling out an outline, but that it wasn't given enough space or detail to fully develop.
The remaining eight chapters detail specific villains, complete with encounter locations, henchmen, allies, and so forth. If you've picked up any of the recent modules, you'll be familiar with the general format. There are brief descriptions (on the order of a few paragraphs) as to how to set each the villain into Eberron or Faerun. Some of the villains are interesting enough, though I think it would be a big stretch to see a given DM use even two of them, much less all of them. (And, after having read about Obould Many-Arrows in the the Hunter's Blades books, do I really need another smarter-than-your-average orc orc leader aspiring to create an empire?) I do see some value for new DMs just to see examples of fleshed-out bosses, just to demonstrate the concepts set out in the first chapter, but I doubt that an experienced DM is going to get a lot out of this book.