Wilderlands of High Fantasy

For those unfamiliar with it, the Wilderlands of High Fantasy is the oldest, most detailed, and perhaps largest campaign setting for Dungeons & Dragons. It was created by Judge's Guild in the early 70s. Gary Gygax even thanks them in the 1e Player's Handbook introduction. Here are a few tidbits to get you started...

Players First
From the introduction to the Wilderlands of High Fantasy:


In the Wilderlands, characters make their own destiny. Barbarians become kings and clerics become high priests. There's nothing to stand in a party's way except conniving despots, horrific sorcerers, and hideous creatures. Have fun with it.

Wide Open Spaces
The Wilderlands are both vast and sparsely populated. Much of the population lives in, or around, one of six large city states spread out across the realm. Outside of these areas, the land is wild and unknown, riddled with the ruins and relics of many past empires. Overland travel in the Wilderlands is dangerous and not to be undertaken lightly, but it can pay large dividends. There's possible treasure around every corner.

Crom not Cromwell
The Wilderlands was created more from the Robert E. Howard mold of fantasy than from historical fantasy. Sure, knights errant are to be found, but players are more likely to run into snake cults and barbarian tribes. Civilization often means corruption or outright evil. Slavery is prevalent in many of the cities of the land. However, good people shine all the brighter in this dark world.

References
For Wilderlands color, try the works of Robert E. Howard, Fritz Leiber, H.P. Lovecraft (for the creeping horror), and Jack Vance. Frank Frazetta's art is on all the sourcebook covers, and it fits the setting perfectly.