Filer’s Files: Worldwide Reports of UFO Sightings (with David Twitchell), Infinity Publishers, 2005

Firestorm: Dr. James E. McDonald’s Fight for UFO Science, Wild Flower Press, 2003

Flying Saucers and Science: A Scientist Investigates the Mysteries of UFOs: Interstellar Travel, Crashes, and Government Cover-Ups, New Page Books, 2008

Flying Serpents and Dragons: The Story of Mankind’s Reptilian Past, revised and expanded edition, The Book Tree, 1999

Followed: Pacific UFO Mystery / Xlibris, 2002

Encounter at Buff Ledge: A UFO Case History

Encounter in the Desert: Case for Alien Contact at Socorro, New Page Books, 2017

Enter the Valley: UFOs, Religious Miracles, Cattle Mutilations, and Other Unexplained Phenomena in the San Luis Valley, St. Martin’s Press, 1999

Extraordinary Encounters: An Encyclopedia of Extraterrestrials and Otherworldly Being, ABC-Clio, 2000

Extraterrestrial Archaeology: Incredible Proof that We are Not Alone, Adventures Unlimited Press, 1994