Orkworld by John Wick, the man behind the Legend of the Five Rings rpg and Seventh Sea.
What I enjoy about Orkworld is... literally 7/8 of the book is culture and world info, history and lore, about the world the players, who are orks, live in.
Some examples:
Dwarves want to perfect swordsmanship, the whole Riddle of Steel thing. They are typical dwarves - shtoonties, they're called.
Humans are like the Roman Empire, out to conquer the world.
Elves are perfect. Literally. However, they are magic-energy beings, who take over bodies and shape them. Elves are terrifying because their moral code comes down to not right and wrong, but Strength and Weakness. Wick takes great lengths in talking about their beliefs with real-world analogies, like the author who lived on ramen and mac and cheese, who framed his first rejection letter over where he worked, and kept at it and kept at it; as he says in there, "His name is Stephen King, by the way."
Halflings - rhoontees as they're called - were hunted to extinction by the Humans. They were peaceful, very Shirefolk like, and went out to meet the humans. The Human Emperor immediately offered a gold coin per rhoontee killed. So, they're no more.
Like I said... a very interesting world with interesting concepts, like the concept of Trouble. Basically, everyone's born with Trouble. Some people have little Trouble, and have easy lives. Others have A LOT OF TROUBLE, and if they're strong, they manage and somehow continue on; heroes have Trouble.
Enough of a rant. Look it up sometime.
