On a September evening in 1976, an object that looked similar to a star, but bigger and brighter, was reported over Tehran, Iran. Deputy General Yousefi at the Air Force command post scrambled an F-4 jet to investigate, but the pilot lost his instrumentation and communications when he flew too close to the brilliant object. Parviz Jafari, who later became a General and is now retired, approached the object in a second jet with a navigator sitting behind him. “It was flashing with intense red, green, orange and blue light so bright that I was not able to see its body. The sequence of flashes was extremely fast, like a strobe light,” he reports. He regrets to this day that he didn’t have a camera with him. But he was able to lock on to the diamond-shaped object with his on-board radar.

Then, four other, smaller, round objects separated from the main one in sequence, and Jafari attempted to fire a heat-seeking missile at each one, as it headed straight towards him. Each time, when they got close, his weapon jammed and his radio communications were garbled, just at the moment he was about to fire. An Air Force General, qualified aircrews in other jets, and experienced tower operators watched these events as they unfolded, from different locations.

I have spent many hours interviewing Jafari in person while researching this case. A three page, once-classified U.S. Defense Intelligence Agency (DIA) document detailing what happened during this incident was released through the Freedom of Information Act. “An inordinate amount of maneuverability was displayed by the UFOs,” the report concluded, adding a list of notes on radar confirmation, electromagnetic effects on aircraft, and physiological effects on crew members. The DIA assessment was that “this case is a classic that meets all necessary conditions for a legitimate study of the UFO phenomenon.”

The ongoing discoveries of earth-like planets in our own galaxy, and the presence of water on Mars, have heightened public curiosity about the possibility of extraterrestrial life. As a corollary to this, there is a renewed interest in the question of unidentified flying objects, which the Air Force, in the 1950’s, defined as: “any airborne object which by performance, aerodynamic characteristics, or unusual features does not conform to any presently known aircraft or missile type, or which cannot be positively identified as a familiar object.”

The subject of UFOs is not a simple issue to address. It is one of the most misunderstood scientific problems we face today – so much so, that many scientists do not even consider it to be in the category of a problem worth studying. There is a great deal of misinformation and prejudice against it, confusion about what a UFO actually is (and isn’t), and attitudes of ridicule have permeated the culture for decades. In fact, taking UFOs seriously has become taboo.

As a result of an extensive study of the factual record, and interviews with the highest level, best-informed sources in the world on this subject, I know these attitudes are wrong. I have spoken with many scientists who take the subject very seriously, and I’m working to facilitate the opening of new doors within the political and scientific establishments to allow for further discovery about UFOs.

It all started for me in 1999, when I was co-producing a daily news show at a California public radio station. A colleague in Paris sent me an exclusive translation of a stunning new French military study about UFOs and their impact on national security. This unprecedented document, called the COMETA Report, marked the first time in any country that a group of such stature had declared that UFOs – solid but as yet unidentified objects in the sky – constituted a real phenomenon warranting immediate international attention.

The thirteen distinguished authors – consisting of four retired generals, an admiral, a police chief, scientists and space experts working independently of the French government – had spent three years analyzing military and pilot encounters with UFOs. In the cases they presented, all conventional explanations of something natural or manmade had been eliminated by teams of experts, and yet these strange objects were observed at close range by pilots, tracked on radar, and officially photographed.

Writing with stark objectivity and matter-of-fact logic, the authors explained that the well-documented sightings they examined cannot be explained by anything known to us, such as advanced military technology or rare natural phenomena. These officials were in a position to find this out, with access to information from official sources. Instead, the objects seem to be “completely unknown flying machines with exceptional performances that are guided by a natural or artificial intelligence.” In their startling conclusion, the authors stated that ”numerous manifestations observed by reliable witnesses could be the work of craft of extraterrestrial origin.” In fact, they stated that the most logical, valid, and rational explanation for these sightings is ”the extraterrestrial hypothesis.” By this they were proposing an unproved theory that needs to be tested, and they stated clearly that the nature and origin of the objects remain unknown.

I was intrigued that such high-level officials would reach such a conclusion, and recognized the implications of their findings. This report was a catalyst for my in-depth journalistic investigation into the UFO subject. Over the years, I have reviewed hundreds of once-secret documents released through the Freedom of Information Act, aviation reports and radar data, corroborated case studies with physical evidence, and scientifically-analyzed photographs. Many declassified U.S. government documents also acknowledge the existence of UFOs, even though, as a matter of policy, our government no longer investigates or tracks UFOs – at least publicly. Project Blue Book, our official Air Force agency which collected reports on the phenomenon, was shut down in 1970.

In addition to studying government documents, I interviewed Air Force generals, pilots, and official investigators from around the world. I learned that foreign governments, including those of Britain, France, Belgium, Chile, and Brazil, recognize that UFOs exist and defy explanation, and have been willing to say so publicly, in formats such as press conferences or in response to questions from the public.

This work culminated with my book, UFOs: Generals, Pilots and Government Officials Go On the Record (Crown/Random House, 2010). High-level officials, including five generals, a former U.S. Governor, and a retired senior scientist from NASA, wrote their own chapters for the book describing both their own remarkable sightings and investigations of UFOs, and the impact of being in such close proximity to something that is not supposed to exist.

It’s important to understand that about 90% of alleged UFO sightings can be explained as misidentifications of ordinary phenomena, such as satellites, planets, weather balloons, or aircraft; thus, the vast majority of sightings are not actual UFOs. I am only concerned with that remaining 10% – containing enough data for officials to eliminate all conventional explanations – which have been investigated by governments and militaries around the world.

I want to stress the most important point of all concerning these investigations: none of these officials claim to know what UFOs are; this has not yet been scientifically determined. We know a great deal more about them than we did in the 1950’s, when the Air Force first encountered them, but they remain unexplained. Therefore, we must take the scientific approach and remain agnostic as to their origin or nature.

So, I ask the reader to step outside the usual debate between the “believers” who proclaim that extraterrestrials have arrived from outer space, and the “debunkers” who argue, with an aggressive defensiveness, that UFOs don’t exist at all. Neither position is correct; neither involves a rational assessment of the facts. There is a wealth of data accessible to anyone who wishes to be discerning and seek it out. For better or for worse, we are stuck with a viable, worldwide record on the phenomenon; we no longer have the luxury of denial. Yet since this challenges our worldview, and is perhaps psychologically threatening for some, reactions tend to be extreme and irrational, based on opinions or disengagement rather than study and thoughtful analysis. A theory, belief, or knee-jerk reaction is not a useful or reliable way to respond to the issue of UFOs, which is much more complex than one would think. It is this type of extreme thinking that fuels the taboo and keeps it in place.

The central and most shocking fact about UFOs is that their existence has been officially verified at the highest levels and documented in official files (again, as unexplained phenomena, not alien spacecraft!). There are solid, three-dimensional objects of unknown origin flying around in our skies, stopping in midair and zooming toward outer space, which are apparently not natural or manmade. They come in a variety of shapes and sizes, usually disc-shaped or triangular, most often silent, sometimes beaming down lights to the ground below. They appear to be metallic, often luminous, and able to maneuver in ways that defy the known laws of physics. They’ve occasionally landed as well, leaving physical imprints on soil while shriveling the leaves of nearby plants with radiation. They have flown alongside commercial airplanes loaded with passengers, and have had physical effects on cockpit equipment. Photographs have captured their image on film, and radar has done the same thing on tracking monitors. All of these physical manifestations have provided ample data for laboratories and technical experts, and much has been learned about the characteristics of the objects.

The witnesses involved in these cases (those officially investigated, multiple witness cases with physical evidence) are highly credible: commercial pilots and aviation professionals; Air Force pilots and military personnel; police officers and scientists. Some of these reports clearly have national security or air safety implications, but most of all, they represent a genuine mystery: something physical is actually there. This “something” demonstrates speeds, accelerations, and other characteristics that challenge our current scientific paradigm. Sometimes the objects act as if under intelligent control, in their responses to human signals or quick escapes from aggressive maneuvers by Air Force pilots. This represents either a threat or an opportunity, depending on how you want to look at it, but, as far as we know, no hostile actions have ever been taken by the UFOs.

On March 13, 1997, over a thousand citizens witnessed massive delta-shaped objects gliding silently over the state of Arizona, between about 8:00 and 9:30pm. Witnesses described gigantic, solid craft that blocked out the stars, with arrays of lights on their edges, which some saw zoom off from a hovering position in the blink of an eye.

The U.S. Government ignored inquiries from state officials, including Senator John McCain, and never offered the public any explanation. Former Arizona governor Fife Symington acknowledged ten years later that he too had witnessed a “craft of unknown origin” on this date, while in office. He did not come forward then due to the climate of ridicule surrounding this subject. “If the sighting affecting so many people in Arizona could have been officially, quickly, and openly investigated, with no stigma attached, all the resulting public confusion and hysteria that I faced as governor could have been avoided,” he told me. This illustrates the serious implications of the taboo, so firmly entrenched that a U.S. Governor felt he had to keep his sighting secret for ten years, rather than come to the aid of his constituents who were also disturbed by what they had witnessed.

More recently, a daylight incident occurred at O’Hare International Airport during the late afternoon rush hour. On November 7, 2006, a disc-shaped object was observed hovering over the United Airlines terminal, before suddenly shooting rapidly upwards and cutting a sharp hole in the cloud bank above. Pilots and other aviation personnel watched it for over five minutes, and reports to the tower were preserved on tape. The FAA declined to investigate and seemed uninterested in the many corroborating reports from UA employees and other airport personnel, dismissing the incident as “weather.”

Much of the American public has grown increasingly frustrated with the pattern of often ludicrous government denials about UFOs, especially as the evidence of their existence has mounted over time. Such dismissals prohibit scientists from becoming openly involved. The questions raised by the UFO phenomenon are deeply disturbing to our accustomed ways of thinking, but they also point to something possibly revolutionary, something that could change our entire worldview. I hope scientists will choose to address the mystery of this phenomenon, and rise above the political problem. The aggregate data, the accumulation of evidence over decades, is utterly compelling, and completely mystifying. Our task now is to use our rational minds coupled with our curiosity to overcome the taboo against taking UFOs seriously.