Net Force Explorers (with Russell Davis)
17. Cloak and Dagger (2002)

Twilight Zone
3. Deep in the Dark (2004)

Shadowrun (with Jean Rabe)
Aftershock (2006)

Murder Most... (with Martin H Greenberg)
Murder Most Medieval: Noble Tales of Ignoble Demises (1993)

Fantastic (with Martin H Greenberg)
Warrior Fantastic (2000)
Knight Fantastic (2002)

Black Cats and Broken Mirrors (1998) (with Martin H Greenberg)
Alien Abductions (1999) (with Martin H Greenberg)
Future Crimes (1999) (with Ed Gorman, Martin H Greenberg)
Star Colonies (2000) (with Ed Gorman, Martin H Greenberg)
Villains Victorious (2001) (with Martin H Greenberg)
The Mutant Files (2001) (with Martin H Greenberg)
Space Stations (2004) (with Martin H Greenberg)
Little Red Riding Hood in the Big Bad City (2004) (with Martin H Greenberg)
In the Shadow of Evil (2005) (with Martin H Greenberg)
Slipstreams (2006) (with Martin H Greenberg)
Army of the Fantastic (2007) (with John Marco)
Man Vs Machine (2007) (with Martin H Greenberg)
Future Americas (2008) (with Martin H Greenberg)

The Valdemar Companion (1990) (with Mercedes Lackey)
The Valdemar Companion: A Guide to Mercedes Lackey's World of Valdemar (2001) (with Denise Little) (see Mercedes Lackey)
Alpha Bravo Delta Guide to the U.S. Navy (2003) (with Walter J Boyne) (see Walter J Boyne)
Unauthorized Dan Brown Companion (2006) (see Dan Brown)