| Title | Year | Note |
| Shadow of a Shade: A survey of vampirism in literature | 1989 | |
| Specter or Delusion?: The Supernatural in Gothic Fiction | 1987 | |
| Dracula: The Vampire and the Critics | 1988 | |
| Vampire in Literature | 1989 | |
| Shadow of the Beast | 1998 | |
| Dark Changeling | 1999 | |
| Sealed In Blood | 2001 | |
| Different Blood: The Vampire As Alien | 2001 | |
| Child of Twilight | 2003 | |
| From the Dark Places | 2003 | |
| Crimson Dreams | 2003 | |
| Dark Dreams | 2003 | |
| Heart's Desires And Dark Embraces | 2003 | |
| Wild Sorceress | 2004 | |
| Beyond the Mundane: Unravelings | 2004 | 2005 EPPIE Award |
| Embracing Darkness | 2005 | |
| Besieged Adept | 2005 | |
| Maiden Flights | 2005 | |
| Night Flight | 2006 | |
| Virgin Blood | 2006 | |
| New Flame | 2006 | |
| Dragon's Tribute | 2006 | |
| Ellora's Cavemen: Legendary Tails II | 2006 | |
| Transformations | 2006 | |
| Tall, Dark and Deadly | 2006 | |
| Tentacles of Love | 2007 | Naughty Nuptials |