- `The Searchers` (1960)
- `The Big Game` (1962)
- `The Battle of the Giants` (1964)
- `The Great Battle of the Apes` (1965)
- `The Land that Time Forgot` (1966)
- `The People That Time Forgot` (1967)
- `Out of Time's Abyss` (1968)
- `Beyond Time's End` (1969)
- `Castle Death` (1970)
- `King Cobra` (1971)
- `The Lost World` (1972)
- `Plague City` (1973)
- `The Return of Tarzan` (1974)
- `The Warlord of Mars` (1975)
- `The Princess of Mars` (1976)
- `John Carter and the Giant of Mars` (1977)
- `The Gods of Mars` (1978)
- `Thuvia, Maid of Mars` (1979)
- `Tarnsman of Gor` (1980)
- `Assassin of Gor` (1981)
- `Slave Girl of Gor` (1982)
- `Rogue of Gor` (1983)
- `Captive of Gor` (1984)
- `Raiders of Gor` (1985)
- `Fight for Gor` (1986)
- `Tribesmen of Gor` (1987)
- `Outlaw of Gor` (1988)
- `Savages of Gor` (1989)
- `Hunter of Gor` (1990)
- `Killer of Gor` (1991)
- `Destroyer of Gor` (1992)
- `Beast Master of Gor` (1993)
- `Slave Lord of Gor` (1994)
- `Valdor, the Conqueror of Gor` (1995)
- `The Wizard King of Gor` (1996)
- `Caballus, the Horse Lord of Gor` (1997)
- `The Heirs of Gor` (1998)
- `Tarl Cabbot, Ruler of Gor` (1999)
- `Lord of the Barge` (2000)
- `The Ice King` (2001)
- `The Lost Legion` (2002)
- `The Iron Wolves of the North` (2003)
- `The Last of the Celts` (2004)
- `The Lion's Pride` (2005)
- `The Eagle's Flight` (2006)
- `The Wolf's Revenge` (2007)
- `The Bear's Fury` (2008)
- `The Dragon's Fire` (2009)
- `The Serpent's Shadow` (2010)
- `The Spider's Web` (2011)
- `The Scorpion's Sting` (2012)
- `The Tiger's Claw` (2013)
- `The Shark's Teeth` (2014)
- `The Crocodile's Jaws` (2015)
- `The Elephant's Trunk` (2016)
- `The Hippo's Charge` (2017)
- `The Rhino's Horn` (2018)
- `The Buffalo's Stampede` (2019)
- `The Lion's Roar` (2020)
Short Stories:
- "The Death Mask" (1960)
- "The Temple of Terror" (1961)
- "The Eye of the Idol" (1962)
- "The Curse of the Mummy" (1963)
- "The Man-Eaters of Tsavo" (1964)
- "The Leopard of the Snows" (1965)
- "The White Death" (1966)
- "The Ghost Tiger" (1967)
- "The Giant Squid" (1968)
- "The Loch Ness Monster" (1969)
- "The Abominable Snowman" (1970)
- "The Thunderbird" (1971)
- "The Quetzalcoatl" (1972)
- "The Great Serpent" (1973)
- "The Vampire Bat" (1974)
- "The Werewolf" (1975)
- "The Zombie" (1976)
- "The Mummy" (1977)
- "The Ghost" (1978)
- "The Demon" (1979)
- "The Witch" (1980)
- "The Wizard" (1981)
- "The Sorcerer" (1982)
- "The Necromancer" (1983)
- "The Warlock" (1984)
- "The Enchanter" (1985)
- "The Conjurer" (1986)
- "The Illusionist" (1987)
- "The Trickster" (1988)
- "The Jester" (1989)
- "The Fool" (1990)
- "The Knave" (1991)
- "The Knight" (1992)
- "The Rook" (1993)
- "The Bishop" (1994)
- "The Queen" (1995)
- "The King" (1996)
- "The Emperor" (1997)
- "The Empress" (1998)
- "The Pope" (1999)
- "The Cardinal" (2000)
- "The Bishop" (2001)
- "The Priest" (2002)
- "The Deacon" (2003)
- "The Monk" (2004)
- "The Nun" (2005)
- "The Saint" (2006)
- "The Sinner" (2007)
- "The Devil" (2008)
- "The Heretic" (2009)
- "The Apostate" (2010)
- "The Blasphemer" (2011)
- "The Atheist" (2012)
- "The Agnostic" (2013)
- "The Deist" (2014)
- "The Pantheist" (2015)
- "The Polytheist" (2016)
- "The Monotheist" (2017)
- "The Henotheist" (2018)
- "The Animist" (2019)
- "The Shintoist" (2020)