He is probably best known as a leading skeptic of UFO sightings and incidents, and he has been a talking head in several documentaries dealing with UFOs. He has appeared in the A&E Network's 1997 documentary "Where Are All the UFOs?", and on the History Channel documentaries "Unsolved History: Area 51" and "Roswell: The Final Declassification". In his 1994 book Watch the Skies!, a critical history of the UFO phenomenon, Peebles writes that: "I am a skeptic. I believe flying saucer reports are misinterpretations of conventional objects, phenomena, and experiences. I do not believe the evidence indicates the Earth is under massive surveillance by disk-shaped alien spaceships." However, Peebles also writes that "these [UFO] conclusions are those of the author; readers [of this book] are encouraged to make up their own minds."
In addition to his UFO research, he has also written numerous books and magazine articles dealing with declassified (formerly secret) Air Force secret weapons projects, and he is a frequent lecturer at conferences and symposiums on aviation history.
Books by Peebles
- Watch the Skies! A Chronicle of the Flying Saucer Myth, 1994. Smithsonian Institution Press. ISBN 1-56098-343-4
- Asteroids: a History, 2001, Smithsonian Institution Press, ISBN 1-56098-982-3 (or 2000, ISBN 1-56098-389-2).
- Twilight Warriors: Covert Air Operations Against the USSR, 2005, Naval Institute Press, ISBN 1-59114-660-7
- The Moby Dick Project: Reconnaissance Balloons over Russia, 1991, Smithsonian Books, ISBN 1-56098-025-7
- Dark Eagles: A History of Top Secret U.S. Aircraft Programs, 1997. ISBN 0-89141-623-4
- Shadow Flights ISBN 0-89141-700-1
- Guardians: Strategic Reconnaissance Satellites ISBN 0-89141-284-0
- Battle for Space ISBN 0-8253-0160-2
- High Frontier: The U.S. Air Force and the Military Space Program, 1997. ISBN 0-16-048945-8
- The Corona Project: America's First Spy Satellites, Annapolis: Naval Institute Press. ISBN 1-55750-688-4.
- Flying Without Wings: NASA Lifting Bodies and the Birth of the Space Shuttle (Smithsonian History of Aviation and Spaceflight) (with Milton O. Thompson), 1999 ISBN 0-947554-78