| title | ISBN-13 | year of publica-
tion | other author(s) |
|---|
| An American Demonology: Flying Saucers Over the White House | 978-1-900486-46-0 | 2005 | Colin Bennett |
| Cryptozoology A to Z: The Encyclopedia of Loch Monsters, Sasquatch, Chupacabras and Other Authentic Mysteries of Nature | 978-0-613-33996-4 | 2001 | Loren Coleman |
| Cryptozoology A To Z: The Encyclopedia of Loch Monsters, Sasquatch, Chupacabras, and Other Authentic Mysteries of Nature | 978-0-684-85602-5 | 1999 | " |
| Encyclopedia of Strange and Unexplained Physical Phenomena | 978-0-8103-8843-7 | 1993 |
| High Strangeness: Ufos from 1960 Through 1979 | 978-1-55888-742-8 | 1996 |
| New Age Encyclopedia | 978-0-8103-7610-6 | 2005 | J. Gordon Melton · Aidan A. Kelly |
| Strange & Unexplained Happenings: When Nature Breaks the Rules of Science | 978-0-8103-9780-4 | 1995 | Nancy Pear |
| Strange Skies: Pilot Encounters With Ufos | 978-0-8065-2299-9 | 2003 |
| The Ufo Book: Encyclopedia of the Extraterrestrial | 978-1-57859-029-2 | 1997 |
| The UFO Encyclopedia: The Phenomenon from the Beginning | 978-0-7808-0097-7 | 1998 |
| The Unidentified & Creatures of the Outer Edge | 978-1-933665-11-5 | 2006 | Loren Coleman |
| UFOs in the 1980s | 978-1-55888-301-7 | 1990 |
| Unexplained!: 347 Strange Sightings, Incredible Occurrences, and Puzzling Physical Phenomena | 978-0-8103-9436-0 | 1993 |
| Unexplained!: Strange Sightings, Incredible Occurrences & Puzzling Physical Phenomena | 978-1-57859-070-4 | 1998 |
| Unexplained: Strange Sightings, Incredible Occurrences, and Puzzling Physical Phenomena | 978-0-7808-0715-0 | 2003 |
| Unnatural Phenomena: A Guide to the Bizarre Wonders of North America | 978-1-57607-430-5 | 2005 |