World of Tiers is a series of connected science fiction/fantasy novels by Philip José Farmer. The central idea of these novels is a set of customized universes, created and ruled by decadent near-immortals. The novels are:

• The Maker of Universes (1965)
• The Gates of Creation (1966)
• A Private Cosmos (1968)
• Behind the Walls of Terra (1970)
• The Lavalite World (1977)
• More Than Fire (1993)

The novel Red Orc's Rage (1991) can be included in the series, but the connection is marginal rather than central.

The overall series title comes from the main 'pocket universe' featuring in the books. The physical rules and structures are set by the whim of the creator, Lord Jadawin/Robert Wolff. Set beneath an endless green sky there is a single main planet, a moon, and a tiny orbiting sun.

The main planet is made in the form of a huge stepped pyramid on five stages, "the surface area on all the levels of this planet, that is, the horizontal area on the tops of the monoliths, equaled the surface area of the watery bodies of Earth. This made the land area more than that of Earth's. In addition, the habitable areas on the verticalities of the monoliths were considerable. These alone probably equaled the land area of Earth's Africa. Moreover, there were immense subterranean territories, great caverns in vast networks that ran under the earth everywhere." Each layer is isolated from the other by enormous cliffs (30-1000,000 ft called Abharhploonta, Doozvillnavava, and Idaquizzoorhruz), although there is no diminuation of atmosphere.

The stages are (bottom to top, largest to smallest):

• Okeanos - watery, Greek, paradise.
• Amerind - prehistoric North America.
• Dracheland - medieval, Germanic.
• Atlantis - was a major civilization, now ruins and jungle.
• Palace of Jadawin.

The stages are populated by the descendents of people and animals snatched from Earth, or beings artificially created by Jadawin.

The Jadawin family (or at least their names) are taken from William Blake's mythology. This mythology is referred to by the characters in the stories (mainly in the 2nd & 3rd books).