Creaciones
| ▲Título▼ | △C▼ | ▲Año▼ | ▲V▼ | ▲Concepto▼ |
|---|
| Creatures of the Mythos ("Malleus Monstrorum") (junto a Marion Anderson, Scott David Aniolowski, Bruce Ballon et al.) |   | 2006 | — | Escritor |
| Creatures of the Mythos ("The Creature Companion") (junto a Scott David Aniolowski, Shannon Appelcline, Bill Barton et al.) | | 1998 | — | Escritor |
| Creatures of the Mythos ("Ye Booke of Monstres II") (junto a Phil Anderson, Marion Anderson, Bill Barton et al.) | | 1995 | — | Escritor |
| Deities of the Mythos ("Malleus Monstrorum") (junto a Phil Anderson, Marion Anderson, Scott David Aniolowski et al.) | | 2006 | — | Escritor |
| Deities of the Mythos ("The Creature Companion") (junto a Phil Anderson, Marion Anderson, Scott David Aniolowski et al.) | | 1998 | — | Escritor |
| The Dreamlands Bestiary (junto a Scott David Aniolowski, K.L. Campbell-Robson, Larry DiTillio et al.) | | 1997 | — | Escritor |
| Equipment & Arms (junto a John Crowe III y Paul McConnell) | | 1993 | — | Escritor |
| Forbidden Books (junto a Kevin Ross y Lucya Szachnowski) | | 1993 | — | Escritor |
| Gods of the Dreamlands (junto a K.L. Campbell-Robson, Sandy Petersen y Chris Williams) | | 1997 | — | Escritor |
| A Guide to Arkham (junto a John B. Monroe y Lynn Willis) | | 1990 | — | Escritor |
| A Guide to Dunwich Environs (junto a John T. Snyder y Carol Triplett-Smith) | | 1991 | — | Escritor |
| Introduction (to "Adventures in Arkham Country") | | 1993 | — | Escritor |
| Introduction (to "Arkham Unveiled") | | 1990 | — | Escritor |
| Introduction (to "H.P. Lovecraft's Dunwich") (junto a John T. Snyder) | ? | 2002 | — | Escritor |
| Introduction (to "Return to Dunwich") (junto a John T. Snyder) | ? | 1991 | — | Escritor |
| Introduction (to "Tales of the Miskatonic Valley") | | 1991 | — | Escritor |
| Introductions ("Worlds of Cthulhu Issue #01") (junto a Adam Crossingham y Frank Heller) | | 2004 | — | Escritor |
| Lost Worlds of the Old West (junto a Kevin Ross y Todd A. Woods) | | 2017 | — | Escritor |
| Lovecraft's Country | | 1990 | — | Escritor |
| Mysterious Innsmouth (junto a Kevin Ross) | | 1992 | — | Escritor |
| Mysterious Places | | 1993 | — | Escritor |
| Orientation | | 1990 | — | Escritor |
| The Professional Investigator (junto a Gary O'Connell y Greg Rucka) | | 1994 | — | Escritor |
| Research & Resources (junto a Kenneth Faig Jr., Paul McConnell, Lucya Szachnowski y Justin Tynes) | | 1993 | — | Escritor |
| The Roaring Twenties (junto a Anne Merritt) | | 1993 | 9.00 | Escritor |
