Races of Eberron (Dungeons and Dragons v3.5 Supplement): A Race Series Supplement (Dungeons & Dragons) (Hardcover)

Interestingly, this is presented not as an Eberron supplement, but uses the presentation and format of the other "Races" books, so it it doesn't have the look of an Eberron book. This is because it is hoped that, even if you don't want to use Eberron, you might like the races on an individual basis. However, all of the detail mentions the Eberron setting all the way through in very specific terms, so a lot of the impact would be lost if that is not actualy used. Basically, it's an throughgoing Eberron supplement, irrespective of what it says in the introduction. In fact, I would say that this is an absolutely core book for anyone wanting to use Eberron, because it really fleshes out not only the main races in question, but also the setting.

For example, the kalashtar are defined partly by their origins as "merged beings" of humans and creatures from the plane of dreams, and also by their opposition to the Inspired from the continent of Riedra. Consequently, this feeds through into their society and outlook, and for their practical philosophies of life, and so on. This explains part of the what is going in in that corner of Eberron, and provides roleplaying and adventure design hints. Similarly, the changelings are described as having a number of philosophies, for the "seemers" who just want to fit in in a specific role, to the "becomers" who revel in their shapeshifting abilities and have multiple identities, to the "reality seekers" who want to be accepted as changelings in their native form. This gives ideas on how to play a changeling, and on the interesting ramifications on their shapeshifting abilities.

Equally useful is the section on the standard races (some of which are not so standard, like drow and goblinoids) and how they fit in with the other races in Eberron. So there are various types of halfling (urban or Talenta Plains huntsmen) and elves (drow, urban, Aerenal and Valenar) and so on, differing quite markedly from D&D standard. This also fleshes out the setting in a very satisfactory way. The various character options and prestige classes are also good (not all of them concentrate on the four "Eberron" races, but there is lots of material on the standard races too).

A note: the Eberron setting is quite fully integrated with the Expanded Psionics Handbook. As such, some races (especially the kalashtar) don't make a whole lot of sense without it. The kalashtar section of the book basically assumes that you have the EPH, so if you don't you may have to adapt significantly. (However, I would suggest that you should get the EPH anyway, as it is virually a core rulebook anyway, and a very good supplement.)

So I give this a pretty substantial thumbs up. In fact, if you like Eberron, you probably need this book.