The Tome of Midkemia is a roleplaying game describing the world of Midkemia. It is also the setting for the Raymond E. Feist novels, given that he was involved in the game's genesis.
The original core supplement The Tome of Midkemia was never published, but several supplements describing aspects of the world were published:
Many of these were later re-published by Chaosium, Inc.
Many of these products are still available as digital products at www.midkemia.com