Races of the Wild contains background information on the elves and halflings, introduces a race of winged humanoids called "raptorans," as well as giving rules for playing wilderness based creatures such as fey and centaurs as player characters.
"One new twist on elves is self-sufficiency and nonspecialization," Skip Williams explained. "The long elven lifespan gives them plenty of time for learning to do things for themselves. Halflings lead something of a double life. Their wandering lifestyle obliges them to seem open and welcome to strangers, but they have secrets they keep to themselves."