World of Tiers

World of Tiers is a series of novels written by Philip José Farmer. • 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) Series related, but not in the main sequence: • Red Orc's Rage (1991)