Short Stories

• Batman in Nighttown (1989) (with Robert Silverberg)
• A Plague of Strangers (1989)
• Inside Out (1992)
• Red Angels (1993)
• My Husband Became a Zombie and it Saved Our Marriage (1994)
• On the Tip of a Cat's Tongue (1994)
• Doing the Angry Centipede (1995)
• First Contact, Sort of (1995) (with Carol Carr)
• The King Who Would Fly (1995)
• A Round of Cards with the General (1995)
• The Spell Between Worlds (1995)
• The Vampire of the Opera (1995)
• A Bone Dry Place (1996)
• Cezanne Was a Capricorn (1997)
• The Glyptodon's Quadrille (1997)
• Dog Is My Copilot (1998)
• A Killing Light (1999) (with Robert Silverberg)
• The Federal Spy And Miz Julia (2000)

Novels

• Thieves' Carnival (1990)
• Bless the Beasts (Star Trek: Voyager series, 1996)
• Crossing Infinity (2005)

Series

Fire in Winter

1. The Mutant Season (1989) (with Robert Silverberg)
2. The Mutant Prime (1990)
3. Mutant Star (1992)
4. Mutant Legacy (1992)

War Minstrels

1. Woman without a Shadow (1995)
2. The War Minstrels (1995)
3. Sister Blood (1996)

Non-Fiction

• Science of the X-Men (2000) (with Link Yaco)
• The Art of Todd Lockwood: Transitions (2003)
• Kong Unbound (2005)

Editing

• Universe 1 (1990)
• Universe 2 (1992)
• Universe 3 (1994) (with Robert Silverberg)
• Meditations on Middle Earth, essay collection celebrating J.R.R. Tolkien (Earthlight, 2001)
• Fantasy: The Best of 2001 (2002) (with Robert Silverberg)
• Scientific American's Secrets of the Periodic Table (2002)
• Science Fiction: The Best of 2003 (2003) (with Jonathan Strahan)
• Fantasy: The Best of 2002 (2003) (with Robert Silverberg)
• Exploring the Matrix: Visions of the Cyber Present, a collection of essays by leading sf authors (St. Martin's Press, 2003)
• Fantasy: The Best of 2004 (2005) (with Jonathan Strahan)
• Science Fiction: The Best of 2004 (2005) (with Jonathan Strahan)
• Science Fiction: The Best of 2005 (2006)
• Fantasy: The Best of 2005 (2006) (with Jonathan Strahan)