Since Laundreu already posted, I may as well. Pfft.
IMC, gnomes were created by an overgod(des) who favors knowledge. Gnomish culture ranges from a "let's see what happens" scientific focus to small groups focused on "folk" or deep knowledge. If you want to find out what's going on in an area, you ask around for a gnome; they're often repositories of gossip, and have prodigious memories. Traveling gnome bards are welcomed in nearly every community, even those normally unfriendly to outsiders, because of their wide repertoire of performance and news. They often use their innate cantrips to illustrate some piece of knowledge. Ordinary gnomes who don't wish to wander often settle down as farmers or craftspeople, while heroicly inclined gnomes often become wizards or clerics. Even gnomes with sorcerous abilities rarely progress as sorcerers; not knowing why or how their power works is maddening for them.
In general, gnomes are fairly healthy, robust people, with more patience with tricksters than most other races since they understand the usual motivation of a prank. When they break the law of the land, it is generally to find out something, or simply to experiment with limits. Gnomish thieves generally steal to find out more about their treasure: i.e., "What does this pretty ring/mummified hand/glowing staff do?" Very wealthy gnomes generally spend their wealth on libraries or institutions of knowledge, and are considered almost barbaric if they don't make said collections open to the public. Most gnomish groups welcome visitors, if only as bringers of news, and can be very hospitable, if rather pushy in their desire to find out everything about their guests. They're very good, however, at getting anyone they find boring out of their abodes.
