Gnomes are sort of out of place in the fantasy world. While in the real world, everyone knows what a gnome is, and they are fairly popular (even occasionally appearing in TV commercials), there is not much of a role for them in a fantasy world, as there is a crowd of other short people. On the "good" side, there are dwarves and hobbits and halflings and kender and smurfs. On the "bad", there are goblins, ewoks, and kobolds. It's hard for gnomes to find a niche. Sometimes they are poor man's dwarves, sometimes hobbits with a big nose, sometimes something else (1st edition AD&D made them into illusionists and tricksters.)
This book presents 3 major types of gnomes. Hill Gnomes are basically like Hobbits, sort of rural folk. Moutain Gnomes are basically like Dwarves, only with a Scottish accent to them, and a sense of humor. Imperial Gnomes are by far the most original concept, being Gnomes that have a Japanese or Korean style culture.
Each gnomish culture gets a very detailed description. Social structure, customs, clothing, etiquette, pastimes, just about everything you'd want to know. The government types are painstakingly detailed. Even their clothing is detailed. Almost more than you'd want to know about gnomes, by the end of the chapter I was almost saying, "gnome mas".
I found Hill Gnomes to be the most likeable sort of gnome. As mentioned, they remind me of Hobbits, or the traditional sort of Halfing (before they were changed to hyperactive children in 3e).
Mountain gnomes, besides being somewhat dwarf like, have a strong caste system. They're supposed to be lawful good, but I'm not sure how that jibes with a caste similar (which IMHO, is inherently unfair, and thus, not good).
Imperial Gnomes get the most pages devoted to them. As mentioned, they are asian flavored gnomes, presumably based on the Japanese empire (at least, there's samurai and such).
I found this sort of gnome to be a bit sureal, especially the pictures of the Gnome Samurai. (Gnome Ninjas I can handle, but Samurai? ). Still, it works out surprisingly well.
It is somewhat odd, while these gnomes get the biggest description of any gnome type, there is really no mention or tie in to them in the rest of the book (the spells, classes, magic items, etc, except for some of the mundane items in the equipment section). While classes and such from "Oriental Adventures" are not open content, the rules stuff from AEG's "Rokugan" sourcebook is, and it happens to have many classes (like the Samurai and the Ninja). It would have nice to have some tie ins with those.
After the chapters on the main gnomish cultures, there's a chapter that is a grab bag of gnome stuff: minor variants, gods, feats, and diseases.
Three more gnome variants get briefly mentioned (and statted up). "Frightlock" gnomes, which are sort of are to Gnomes what the Addams family is to humans, sort of spooky, necromancer types. Then there are the "Oakcap" gnomes, which are basically wilderness or outdoors sorts of gnomes. They actually are like the gnomes I used in my home brew world (as it's the obvious development of the garden/lawn gnome). There's also the "Toedirt" gnome, which seems to be aimed at making fun of poor people, being based on their stereotypes. (As I live in a poor, rural community, needless to say, I didn't find these all that amusing). These are all short entries, and probably deserved to be fleshed out more.
There's a whole gnomish pantheon. While the concepts/archetypes of the gods are pretty solid, some of the names are a bit silly, even for gnomes. For instance, the goddess of the house is called "Hazel Broomsweep". The god of law they worship is called "Continuo". The goddess of nature of theirs is called "Knotaleafa". The big or main god, is called "Oserien Anntilien Mareleos", which sounds like a name a Goth would take. But to a certain extent, you do expect gnomes to have silly names.
The feats are something of a mixed bag. A lot of them seem to be broken, or in some cases, similar but worse to existing feats. For instance, several feats give a +2 skill bonus to a skill, but only in some cases, like only to feys or big people. So it's generally not as good as many skill bonus feats (the general rule is, +3 to one skill, or +2 to 2 skills), it's more limited in application.
Similarly, later on in the book, I thought some of the prestige classes are a bit unbalanced or not fully thought out, rules wise.
For instance, "The Stump Knight", a sort of gnome that is expert at attacking tall people. It got all great saves, plus the best base attack bonus, plus a slew of special abilities. Prestige classes should be somewhat better than a core class, but not that much better.
The "Burrow Savage" is also probably too good. Some of the spell casting prestige classes, though better, power wise, have non-standard save progressions, which is something that bugs some people (at least me).
The part I liked the most about the book are the magic items for gnomes. They are perhaps a bit silly, but fit more in my notion of a gnome (though not really the gnomes in this book). For instance, there's a variety of magical gnomish hats (those conical floppy things), which they tend to wear in my game world, but which they don't seem to in any illustration in this book.
Many of the new spells and magic items are directly named after a specific gnome who created them. I really liked this, because each one has their own specialty. For instance, the spells by Bandycook "The Clean" Thigwistle deal with cleanliness or cleaning. The named spells are perhaps not the most obviously useful, but in the generic section, there are a lot of illusion spells that could find a use. And the weird spells are great for filling up spellbooks your PCs might find.
Many also are puns. Gnome being one of the most pun-able words around. For instance, there are a couple of items called "Gnome Ann's" so and such. (Gnome Ann being an island, not a gnome. Think about it).
Physically, the books is pretty good. The layout is clean, and it's easy to read. There's a table of contents and an index.
The art is excellent, and there is a lot of it. The two artists are both very good, but have a contrasting style. One uses mostly line art, that is, just black & white, and is a bit comic book-ish, while the other has a more realistic style, not photo-realistic, a bit more stylized, but real looking, and uses shading or textures (I'm not really up on my art terms).
Well, the book is somewhat rough when it comes to rules - especially the feats - it definitely needs a d20 rules expert revising it (though it's still better than Fast Forward products). But I did like many of the ideas, and the magic items. And it's well illustrated. C, if not for the rules problems, it would be higher. Like many smaller press products, what it lacks in polish is more than made up for in enthusiasm, which makes the book enjoyable to read.