Bibliografi

1994  Of Saints and Shadows *

1995  Angel Souls and Devil Hearts *

1995  Beach Blanket Psycho (ungdomsbog) *

1995  Bikini (ungdomsbog) *

1997  Halloween Rain [w/Nancy Holder] *

1997  Hellboy : The Lost Army *

1998  Blooded [w/Nancy Holder] *

1998  Child of the Hunt [w/Nancy Holder] *

1998  Of Masques and Martyrs *

1999  Body Bags *

1999  Immortal [w/ Nancy Holder] *

1999  Sins of the Father *

1999  Soul Survivor *

1999  Strangewood *

1999  The Gatekeeper, Book One–Out of the Madhouse [w/Nancy Holder] *

1999  The Gatekeeper, Book Three–Sons of Entropy [w/Nancy Holder] *

1999  The Gatekeeper, Book Two–Ghost Roads [w/Nancy Holder] *

1999  Thief of Hearts *

2000  Head Games *

2000  Meets the Eye *

2000  Skin Deep [w/Rick Hautala] *

2000  Spike & Dru: Pretty Maids All in a Row *

2001  Brain Trust [w/Rick Hautala] *

2001  Burning Bones [w/Rick Hautala] *

2001  Hellboy: The Bones of Giants *

2001  Predator and Prey *

2001  Prowlers *

2001  Straight On ‘Til Morning *

2001  The Lost Slayer – Parts 1 through 4 *

2002  Force Majeure [w/Tom Sniegoski] (ungdomsroman) *

2002  Oz: Into the Wild*

2002  The Ferryman *

2002  The Wisdom of War *

2002  Wild Things *

2003  Monster Island [w/Tom Sniegoski] *

2003  The Gathering Dark *

2003  Hollow earth

2004  Den umagiske 1: I Nikodemus’ tjeneste (fra 12 år) 

2004  Den umagiske 2: Dragehemmeligheder (fra 12 år) 

2004  The Boys Are Back in Town *

2004  The Nimble Man (w/Tom Sniegoski) *

2005  Accursed [w/Amber Benson] *

2005  Den umagiske 3: Slave i spøgelsesilden (fra 12 år) 

2005  OutCast: Wurm War [w/Tom Sniegoski] *

2005  The Tears of Furies [w/Tom Sniegoski] *

2005  Throat Culture [w/Rick Hautala] *

2005  Wildwood Road *

2006  Stones Unturned [w/Tom Sniegoski] *

2006  The Borderkind *

2006  The Myth Hunters *

2006  Witchery [w/Amber Benson] *

2007  Crashing Paradise [w/Tom Sniegoski] *

2007  Hellboy: The Dragon Pool *

2008  Poison Ink (ungdomsroman) *

2008  Soulless (ungdomsroman) *

2008  The Lost Ones *

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