An electrical engineer and senior editor for Aviation Week and Space Technology, Philip Klass began investigating UFOs in 1966 after participating in a panel discussion on the subject for the Institute of Electrical and Electronics Engineers (IEEE). From that time forward Klass has investigated UFO sightings in an effort to find a credible prosaic explanation, and became one of the most widely recognized UFO "debunkers." A founding member of the Committee for the Scientific Investigation of Claims of the Paranormal (CSICOP), serving on the Executive Council and the UFO subcommittee, Klass has authored seven books and numerous articles on UFOs, including the Skeptics UFO Newsletter in 1989. In the early 1970s, he became interested in space based weapons, and began collecting material related to the Strategic Defense Initiative (SDI) for a possible book. The Klass Collection relate to his forty-plus years of investigating UFO sightings, and includes correspondence with many of the leading UFOlogists, both pro and con. The collection contains case files, subject files, and correspondence. In addition, Klass' SDI material is included.

The geneticist Milislav Demerec emigrated from Yugloslavia in 1919, spending nearly his entire career in the Department of Genetics at Cold Spring Harbor Laboratory. Working initially on the genetics of maize and later on Drosophila virilis, his research interests included radiation and chemical mutagenesis, and during the Second World War, penicillin and the genetics of antibiotic resistance. Demerec served as head of the laboratory at Cold Spring Harbor from 1941 until 1960. The Demerec collection contains the extant professional papers of Milislav Demerec, dating primarily from the time of his arrival at Cold Spring Harbor until his retirement. In addition to his correspondence with colleagues, the collection includes interesting material on the administration of Cold Spring Harbor laboratory during the 1940s and 1950s, data and research notes, material relating to professional organizations (e.g. Genetics Society of America, American Society of Naturalists), a lengthy series of lectures given by Demerec, and a large number of photographs pertaining to Demerec's research, but also to his colleagues and Cold Spring Harbor itself. There is also a Register of visitors to the laboratory (1927-1945) and a Milislav Demerec reprint list.