Having spent years of research, thousands of dollars, and countless hours compiling and writing, now my project is finished.

This comment was included in a personal note accompanying Loren Gross' final publication, The Fifth Horseman of the Apocalypse, UFOs: A History, July-December 1963 (2005); marking the culmination of a 30-year effort to chronicle the modern history of the UFO phenomenon. During this period, around 11,000 pages were published in over 100 monographs, which were privately distributed to an active group of colleagues.

Loren's research began in the 1960s pouring through newspaper collections at various libraries, while commencing at the Bancroft Library in Berkeley, which provided a cache of early airship reports in central California resulting in one of the first monographs, The UFO Wave of 1896 (1974). His first acquisition was a unique collection of newspaper clippings from Fortean author Vincent H. Gaddis, covering the Swedish ghost rockets and the beginning of the modern UFO era. Over time, the project quickly burgeoned into a wholesale effort to assemble UFO-related material from around the world, and grew to include the earliest records of the USAF investigations; the news clipping collection of the National Investigation Committee for Aerial Phenomenon; the collection of the 1952 UFO clipping service contracted by the USAF; and the holdings of several private individuals. Most notably, the contributions of Dr. Leon Davidson now archived at Columbia University; Robert Gribble's collection and source notes for the years 1800-1996; as well as materials from the extensive personal archives of Barry Greenwood.

Loren elaborates further:

I checked every frame of the USAF Project Blue Book microfilms for the years 1947-1963. There are many Information Only cases in the records, but also, I might add, there are news clippings, magazine articles, and items from civilian UFO publications. Over the years I was able to compare the PBB records with many other sources including, APRO, CUFOS, NICAP, Dr. James McDonald's papers, Ruppelt, various newspaper clipping collections such as Gribble's, and every UFO book available, etc. Remarkably, there is very little overlap aside from well-known incidents. The Air Force explanations are a joke and I paid little attention to them. Having reviewed tens of thousands of sighting reports I did not use every case while compiling the UFO histories—only the ones I thought were the best. 

Loren E. Gross (left) presented with an honorable discharge from the Richmond, CA, Ground Observers Corps in 1953.

Loren's approach to the raw material forgoes explanation for the myriad reports; rather, similar to 19th century natural history studies, the primary focus is on observational descriptions—what the witnesses reported seeing. The result is a day by day chronology of the UFO controversy, even at times detailing minute-by-minute accounts, while including the actions and attitudes of official and military agencies, various scientific organizations, and moreover, the corresponding reactions within popular culture to the mystery of the unidentified flying objects.

The series also chronicles pranks, hoaxes, and the often circus-like atmosphere that arose during times of increased UFO sightings. On the fringe, otherworldly belief systems and conspiracy theories spawned alongside the vacillations of official and academic interest, while the less-than-rigorous investigation of reports invited a wide variety of opinions and beliefs. Literally thousands of published accounts are available on the subject, and there is an equally vast body of amateur literature, which contributes little to our understanding of the underlying phenomenon. Nevertheless, through it all, Loren manages to balance the presentation revealing previously unexplored aspects of the multi-layered and complex nature of the phenomenon.

During the years writing the UFO history series, well over 150,000 pages of official UFO documents from the U.S. and other governments were released, while ongoing efforts by numerous UFO organizations, and a renewed interest in historical research provided abundant supplementary material [in particular, by Project 1947 director Jan Aldrich]. At first, monographs were revised and updated but as the pace of new material proved overwhelming it was decided to publish a subsequent series of supplemental notes for each respective time period (resulting in an additional 45 monographs).

Along the way Loren added a subtitle, referring to the rather cryptic 1950s pronouncement by Dr. Lincoln La Paz, head of the Institute of Meteoritics at the University of New Mexico and early USAF UFO project consultant, that UFOs are The Fifth Horseman of the Apocalypse. In this instance, the reference was to the Greek apokalyto meaning to reveal, or to disclose something that is hidden.

Loren had originally intended to complete the series with the year 1959, however, during a phone conversation I off-handedly suggested that generally most people don't consider the 1950s ending with the commencement of the new decade, but rather, with the assassination of President John F. Kennedy and ensuing countercultural movement. Fortunately, Loren carried on publishing eight additional monographs for the years 1960-1963—an era previously regarded as a low point for UFO reports. In a recent interview, he expressed his decision to end the series as a result of the ensuing controversy in the early 1960s following the Betty and Barney Hill abduction aboard a UFO. After well-over a decade of exposure to a steady stream of more or less objective media reports, the Hills' story was the first account of face-to-face contact with UFO occupants to receive extensive media coverage, and introduce the possibility that subjective experience, fueled by cultural influences or false memories could account for the phenomenon. From a historical perspective, this proved to be a watershed event that dramatically influenced public consensus concerning the nature of the UFO phenomenon and radically changed the debate. 

After so many years and with the author's support we are pleased to present the entire series to a wider audience. UFOs: A History will undoubtably endure as reliable source documentation, and basis for future historical studies of the early days of the modern UFO phenomenon. This is indeed what Loren had hoped to accomplish, while acknowledging the contributions of many individuals over the years who have shared in the history.

— Jan Aldrich and Thomas Tulien