I'm generally wary about race-oriented RPG supplements, especially for d20 lines. For some reason, they nearly always just don't sit well with me. Too often they seem to be an attempt to cram as many new races as they can, but, naturally enough, these races lack the detail and range of options of those found in core books. See the Ultimate Alien Anthology for WotC's Star Wars line -- most of the races found in the book are given only the barest minimum description and background, and the new Prestige Classes and Feats are generic enough to apply to anyone. Even a good portion of the new equipment listed is for races from the core book. Then, of course, there's Savage Species, from the D&D 3rd edition line, which served better as a highlight to the problems with their approach to more powerful races than as a guide to including characters who aren't one of the core seven species. A successful race guide would need to both have decent basic mechanics for the new races, as well as to offer a decent set of options for these races to establish them as more than pale shadows of the core races.
The Advanced Races Guide for Paizo's Pathfinder line does exactly that, without sacrificing volume for detail.
So, the basics -- the Guide gives us thirty new races, divided into "featured" and "uncommon" -- no, I'm not exactly sure why. I at first thought that the divide was a result of some of the "uncommon" races being limited to certain areas within the Pathfinder setting, Golarion, but then I noticed that the "featured" list included drow and tengus, who are normally only found in the Darklands and Tian Xia, respectively, just like the svirfneblin and kitsune, who get "uncommon" treatment. That little point aside, though, each of the races gets a sizeable list of alternate racial traits to allow for customization, as well as new feats, class archetypes, spells, and equipment. For the sake of completeness, the "big seven" -- the core races -- are once again presented with their alternate traits (many reprinted from the Advanced Player's Guide), as well as racial subgroups designed using these alternate traits, along with additional class archetypes and feats for them, as well. To wrap it all up, we're given a set of guidelines for building new races. The new system is modular, giving designers a pool of "racial points" with which they can buy traits from a variety of categories. There aren't really any limits to what can be built, with templates available even for construct- and undead-type races. From what I've thrown together as experiments, the results of the process seem rather balanced, although I'll be giving them a shakedown in my Jade Regent game where possible.
It may not be all sunshine and kittens for some players, though. The ongoing problem of balance rears its ugly head, since the ability bonuses and powers for some races seem to outstrip what's available for other races. WotC used level adjustment to account for these disparities, but that actually unbalanced such characters in the other direction as play progresses. The Advanced Race Guide addresses the early unbalancing aspect of more powerful races by doing...nothing at all. Now, I should note that none of the new races come with any racial hit dice (although there are some examples in the race building chapter of races that normally have hit dice; the versions found here have no racial hit dice), which would unbalance matters even later in play, but the book does absolutely nothing to address basic ability disparity. In either direction. The aasimar and hobgoblins, for example, get away with a net +4 to their abilities (compared to the core races' net +2 bonus), while goblins have no net bonus, and orcs are stuck at a net -2. The latter races don't get any new powers to help boost them up, either. This may seem like completely incompetent design at first, but I'd say that, in the long run, it actually doesn't matter. The reason level adjustment in D&D 3 is generally considered a failed balancing factor is because it continues to affect characters long after the differing ability modifiers cease to have any impact on play, as ability bonuses are overwhelmed by the sheer number of other bonuses granted by classes, feats, spells, magic items, and so forth. It may seem like a big deal early on, but quite frankly that will fade, and ultimately choice of race will become more a matter of a character's flavor than mechanics. Well, almost... Some disparity remains -- an orc wizard just isn't going to be as good as an elven wizard at any level, for example. Some of new mechanics do address that issue, such as the Scarred Witch Doctor archetype for orc Witches, which makes the class Constitution- rather than Intelligence-dependent, or the tiefling Fiendish Sorcery ability, adding to the character's effective Charisma if they're Sorcerers using one of the fiendish bloodlines. The writers seem well aware that sometimes, players are going to want to go with an unusual race/class combination, and do make efforts to make some of those builds, where they make sense from a flavor perspective, work as well as a more traditional combination.
So if the mechanics ultimately make sense, what about the choice of races presented? They do seem to have hit the more popular choices, including the various planetouched (aasimars, tieflings, and the various elemental types), drow (with a whole host of feats dedicated to advancing toward the "noble drow" presented in the Bestiary), the remaining two major goblinoid races, and kobolds. There's a great deal of attention paid to races from lands other than the Inner Sea area of Golarion that Pathfinder materials usually focus on, including raven-like tengus and kitsune from the oriental-themed Tian Xia and samsarans and vishkanya that (if the names are any indication) are tied to the East Indian-like Vudrani. In the end, I would have to say that just about anything a player would want to bring to my table could be found in this book (with the exception of a few players who enjoy seeing my scowly face).
So, how does the book look, then? Well, I have to say...eh. Next to some of the other games I play regularly these days -- the beautiful elegance of L5R 4th edition or the gritty, high-tech Shadowrun -- the Pathfinder books have never really stood out visually speaking, and the Advanced Race Guide is no exception. Each core race get three pictures each, favored races get two pictures, with one each for the uncommon races, and all thankfully not recycled from the various Bestiary volumes or other books that have addressed these races, but there's nothing really striking or memorable about them. Aside from that, the only other artwork can be found at chapter breaks, as seems to be normal for the Pathfinder line. The focus here is quite obviously on the text, with the artwork there only to give a general impression of how these races look.
Final thoughts: the Advanced Race Guide handles the problem of presenting a properly wide variety of adequately fleshed-out races rather well. While it can be a little disheartening to see that the core races get a bit more coverage than the newer races, ultimately the level of detail that is given to those newer races should be more than enough to satisfy any player. Any who aren't satisfied can turn to the race building chapter and put together just about anything. It's a great addition to the Pathfinder library, more than living up to the level of quality I expect from the Paizo team.
Style: 3. This isn't a book that relies on aesthetics to draw in a reader. No problems, but nothing special.
Substance: 4. Aside from some unusual choices for inclusion in the book, and perhaps a bit too much space spent on the core races and their mechanics (which we've mostly seen elsewhere), we get a solid, working selection of species to work with.