The physicist W.F.G. Swann was a pioneer in high energy physics and the study of cosmic rays. Climbing the academic ranks from the University of Sheffield to the Universities of Minnesota, Chicago, and Yale, Swann was selected as the first director of the Bartol Research Foundation of the Franklin Institute in 1927, and remained there until his retirement in 1959. An able administrator and excellent mentor, he was best known for his popular work on the new physics, The Architecture of the Universe (1934) and for his research on cosmic rays. Avocationally, he was an accomplished cellist and in addition to performing, he helped organize and support the Swarthmore Symphony Orchestra and other local groups. He died at his home in Swarthmore in 1962. The Swann Papers consist of 41 linear feet of correspondence, class notes, lectures, and photographs documenting Swann's career at the Bartol Research Foundation from 1927 until the end of his life. The collection is wide ranging, touching on atmospheric electricity, particle acceleration, atomic bomb defense, atomic energy, electrets, electrodynamics, magnetism, music, quantum theory, radiation, relativity and Einstein, science and civilization, stratospheric flights (by balloon and airplane), thermodynamics, psychic science, and wave mechanics. It is particularly rich for study of the history of cosmic ray research and the Bartol Institute, and for study of the popularization of modern physical sciences.

Edward Uhler Condon was a theoretical physicist at Princeton University and Westinghouse Laboratories who later served as director of the National Bureau of Standards (1945-1951), and as the director of research and development (1951-1954) and consulting physicist (1954-1974) at Corning Glass Works. The Condon Papers includes correspondence, notebooks, writings, photographs, and other materials concerning Condon's education, teaching, and his government, industrial, and academic.

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.