The UFO problem is a real one. It has involved military personnel around the world for more than fifty years, and is wrapped in secrecy. Over the years, however, enough pieces of the puzzle have emerged to give us a sense of what the picture looks like. What I have tried to do is very simple: to use as many of those pieces as possible in constructing a clear, straightforward, historical narrative of the UFO problem, focusing on the national security dimensions.

Considering the number of books about UFOs, it is curious that one like this is so rare. And yet it is. Although there are some excellent sources about this subject, much of the field's writing is rather insular, so that few people are acquainted with it. I believe that this book, on the contrary, will be useful to experienced researchers as well as those with little prior knowledge of the subject.

I have tried to weave together three strands of narrative that have important relationships to one another: (1) UFO reports themselves, with an emphasis on military encounters; (2) the response to UFOs by national security organizations in the U.S.; and (3) additional activities by American national security groups that, while not directly UFO-related, still provide important context to the problem, and at times unique insights and connections. Fundamentally, this is a book about the concern that military-intelligence organizations have toward UFOs, and their concealment of that fact from the public.

Despite the great amount of information I've presented in this book (one of my readers called it "staggering"), I have tried to make it easy. Each of the book's nine chapters is broken down into a manageable number of sub-chapters, making these 500-plus pages a bit more digestible. I also prepared an appendix listing all of the military UFO encounters described in this book – nearly 300. Mainly, however, I have expended as much energy as possible to make this book concise and informative. Your time as a reader is valuable. I have no desire to waste it.

I have selected the period of 1941 to 1973 for this first volume, and intend to complete a second volume that will take the story through the remainder of the 20th century. The early period is especially important to understand, if for no other reason than to analyze the question of UFOs as experimental technology. Today, everyone understands there are secret experimental aircraft that might pass for UFOs. Whether this was the case in the mid-20th century is explored in the narrative of this book. The implications are important, if one concedes UFOs to be objects, and not merely natural phenomena. The early period is also important because it was still possible in some instances to obtain first-rate information from inside sources, much of which received confirmation in later years. UFO information was always subject to secrecy protocols, but such secrecy was not necessarily as complete in the early period as it became later.