English and Italian covers.

The Humanx Commonwealth

• Midworld (l975) review
• Cachalot (l980)
• Nor Crystal Tears (l982)
• Voyage To the City of the Dead (l984)
• Sentenced to Prism (l985)
• The Howling Stones (l997) chapter
• Icerigger Trilogy review
  • Icerigger (l974)
  • Mission to Moulokin (1979)
  • The Deluge Drivers (1987)
• The Founding of the Commonwealth Trilogy
  • Phylogenesis (1999) chapter
  • Dirge (June 2000) chapter
  • Diuturnity's Dawn (not yet published)
• Flinx and Pip Adventures
  • For Love of Mother Not (l983)
  • The Tar-Aiym Krang (l972) review
  • Orphan Star (l977) review
  • The End of the Matter (l977) review
  • BloodHype (l973) review
  • Flinx in Flux (l988)
  • Mid-Flinx (l995) chapter
  • Reunion (not yet published)

The Spellsinger Series

• c Spellsinger at the Gate (l983)
• Spellsinger (l983)
• The Hour of the Gate (l984)
• The Day of the Dissonance (l984)
• The Moment of the Magician (l984)
• The Paths of the Perambulater (l985)
• c Season of the Spellsong (l985)
• The Time of the Transference (l986)
• c Spellsinger's Scherzo (l987)
• Son of Spellsinger (l993)
• Chorus Skating (l994)

Movie Novelizations

• Dark Star (l974)
• Luana (l974) note
• Star Wars (l976) (Ghostwriter for George Lucas) review
• The Black Hole (l979)
• Alien (l979)
• Outland (l98l)
• Clash of the Titans (l98l)
• The Thing (l982) review site/info
• Krull (l983)
• The Last Starfighter (l984)
• Starman (l984)
• PaleRider (l985)
• Aliens (l986)
• Alien Nation (l988) note
• Alien 3 (l992)
• Star Trek: The Motion Picture (Date?) (Ghostwriter for Gene Rodenberry) site/info

The Damned Trilogy

• A Call to Arms (l991)
• The False Mirror (l992)
• Spoils of War (l993)

• With Friends Like These... (l977)
• ...Who needs enemies (l984)
• The Metrognome and Other Stories (l990)
• Smart Dragons, Foolish Elves (l99l) (Editor)
• Betcha Can't Read Just One (l993) (Editor)

• Star Trek Log One-Ten (l974-l978) (based on the animated cartoons)
• Splinter of the Mind's Eye (l978) review
• The Man Who Used the Universe (l983)
• The I Inside (l984)
• ShadowKeep (l984)
• Slipt (l984) review
• Into the Out of (l986)
• Glory Lane (l987)
• Maori (l988)
• To The Vanishing Point (l988)
• Quozl (l989)
• Cyber Way (1990)
• Cat-A-Lyst (l99l)
• Codgerspace (l992)
• GreenThieves (l994)
• Montezuma Strip (l995)
• Life Form (l995)
• Design for Great Day (l995)
• Alien Omnibus (l995)
• Mad Amos (l996) chapter
• Dinotopia Lost (l996) site/info
• The Dig (l996)
• Jed the Dead (l997)
• The Marexx (Builder, Vol. 1) (Foster is creating an interactive online story with MagicMaker, although this site seems to have been down for a while.)
• Parallelities (1998) review chapter
• Journeys of the Cathechist Series
  • Carnivores of Light and Darkness (1998) chapter
  • Into the Thinking Kingdoms chapter
  • A Triumph of Souls (not yet published) chapter
• The Hand of Dinotopia (1999) site/info note
• Interlopers (not yet published)

• GURPS Humanx site/info
• GURPS For Love of Mother-Not