* The Mind Parasites (1967)
* Ice From the Sun (1968)
* Chocky (1968)
* Time Out of Mind (1969)
* The Space Vampires (1976)
* The Weirdstone of Brisingamen (1978)
* The Warlock's Book of Prophecies (1979)
* The Deep (1980)
* The Hills of the Dead (1982)
* Warriors of Shadow (1983)
* The Garden of Rama (1985)
* Red Moon Rising (1986)
* The Shrine (1988)
* Shadow Dancers (1989)
* The Hall of the Mountain King (1990)
* The Children of Atlantis (1992)
* Dark Spaces (1993)
* The Chariots of the Gods (1995)
* Threshold (1998)
* Children of the Shadow (2001)
* Dragonbane (2003)
* The Iron Fist (2005)
* The Last Legend (2007)
* The Legacy (2009)
Short Stories:
* The Man Who Came Early (1963)
* The Wind from Nowhere (1963)
* Children of the Atom (1964)
* The Small Ones (1964)
* No Place Like Earth (1965)
* Stranger in Paradise (1965)
* The Deathday Doll (1966)
* The Time-Swappers (1966)
* The Secret Room (1967)
* The Devil's Alphabet (1968)
* The Man Who Could Walk Through Walls (1969)
* The Garden of Rama (1969)
* The Man Who Loved Alice (1970)
* The Deathday Doll and Other Stories (1972)
* The Weirdstone of Brisingamen (1978)
* The Warlock's Book of Prophecies (1979)
* The Deep (1980)
* The Hills of the Dead (1982)
* Warriors of Shadow (1983)
* The Garden of Rama (1985)
* Red Moon Rising (1986)
* The Shrine (1988)
* Shadow Dancers (1989)
* The Hall of the Mountain King (1990)
* The Children of Atlantis (1992)
* Dark Spaces (1993)
* The Chariots of the Gods (1995)
* Threshold (1998)
* Children of the Shadow (2001)
* Dragonbane (2003)
* The Iron Fist (2005)
* The Last Legend (2007)
* The Legacy (2009)
Non-Fiction:
* The Encyclopedia of Science Fiction (1979)
* The Science of Science Fiction (1985)
* The History of Science Fiction (1985)
* The World of Science Fiction (1986)
* The Future of Science Fiction (1987)
* The Dictionary of Science Fiction (1988)
* The Illustrated History of Science Fiction (1989)
* The Encyclopedia of Fantasy (1990)
* The Science of Fantasy (1991)
* The History of Fantasy (1991)
* The World of Fantasy (1992)
* The Dictionary of Fantasy (1993)
* The Illustrated History of Fantasy (1994)