The opportunity to study Unidentified Flying Objects at all is simply a gift from the witnesses; we would be totally ignorant on this subject without their accounts. I am grateful that many thousands of people who saw something strange in the sky were not afraid to tell somebody about their experiences. I am further indebted to the many researchers who have diligently investigated the individual sightings and shared their findings in various publications. These sources of information are carefully cited throughout the text. The literature on UFOs, however, is so extensive that it has not been possible to pinpoint and credit all authors who may have influenced my thinking. Their contributions must come under a blanket acknowledgment that is equally sincere. No slight is intended to writers who have been ignored, even though their works may be well-known and significant.
I am grateful to the artist, Hal Crawford, for his excellent illustration that is used with the kind permission of Hayden C. Hewes, Director, International UFO Bureau, P.O. Box 1281, Oklahoma City, Oklahoma 73103.
The many frustrations of writing a book in a perplexing field were greatly mollified by Mrs. Judy Vilar whose spirit remained bright as she typed untold numbers of final drafts that, alas, proved to be only preliminary.
Also deserving of thanks are my wife, Carol, grown children, Ann, Kathy, and Nancy, and, rounding out the household while attending college in the U.S., Miss Gunilla Bexar from Finland. They pretended not to notice that the old man went crackers and started talking a lot about flying saucers and other improbable things, even enduring his snippy demeanor when progress was too slow.