Val Logsdon Fitch, (1923-2015)was born on March 10, 1923, in Merriman, Nebraska, in the remote Sandhills region in the north of the state. During WWII, he was drafted and sent to Los Alamos, N.M., to work as a technician on the Manhattan Project. While there, he helped design the detonator for the atomic bomb that was tested at Alamogordo and later dropped on Nagasaki, Japan. He shared the 1980 Nobel Prize in Physics with James Cronin for work that revealed a surprising imbalance in the laws of nature and helped explain why the collision of matter and antimatter has not destroyed everything in the universe. Their discovery of CP (charge parity invariance) violation was the result of experiments that included four objectives: to test the anomalous results of Adair, et al, to study the regeneration phenomena under a variety of conditions in different materials, to set new limits on the decay of the long-lived neutral K to two pions, and to check for the presence of neutral currents in strangeness changing decays. The Val Logsdon Fitch Papers include his research of K mesons, the innovation of the velocity-selecting Cherenkov counter that separated K+ from protons and pions in the beam, neutral kaons, CP violation in proton-antiproton interactions, the 'gap' method invented by Fitch to take measurements of KL - KS mass difference, a search for short-distance gravitational forces and finally, strange dibaryons. Dr. Fitch used particle accelerators to perform his experiments including the Bevatron, the Cosmotron, the accelerator at the Fermilab and the superconducting super collider at CERN, Geneva, Switzerland. The collection is divided into XV Series.

John Archibald Wheeler (1911-2008) was a leading theoretical physicist of the twentieth century, contributing particularly to the fields of general relativity, gravitation, and quantum mechanics. Wheeler was a pioneer in the study of black holes, celestial phenomena which he named. (He had a penchant for creating new terms in physics, and is credited with naming other phenomena such as geons, wormholes, and quantum foam.) Wheeler is also known for his work in atomic and nuclear physics. In 1939, he and Niels Bohr co-authored a paper that gave the basis for recognizing that Uranium 235 and Plutonium 239 are highly fissile, a milestone in the understanding of atomic energy. Wheeler believed in the importance of public service, assisting in the U.S. war effort to develop the atomic and hydrogen bombs, and served as a scientific advisor to numerous government agencies. During a prolific academic career that spanned seventy years, Wheeler taught physics to thousands of undergraduate students at Princeton University and the University of Texas, and mentored more than fifty Ph.D. students. The Wheeler Papers provide an extensive look into the expansive career of John Archibald Wheeler, the pioneering and award-winning theoretical physicist. Comprised of 150 linear feet, this large collection contains a wide array of materials including correspondence, subject files, manuscripts by Wheeler, papers by colleagues and students, research notes and notebooks, photographs, awards, and audiovisual materials. The collection provides much insight in to Wheeler's lengthy career as a scientist, scholar, and teacher. The bulk of the material is from the 1950s to the 1990s and covers the wide scope of his professional endeavors, from his teaching at Princeton University and the University of Texas, to his many publications, to his consultation work with government agencies, industry, and atomic energy projects, to his numerous public talks and lectures.

One of the most influential statisticians of the twentieth century, John Wilder Tukey (1915-2000) played a key role in both the development and study of statistics. Upon receiving his Ph.D. in mathematics in 1939 from Brown University, he joined the faculty at Princeton; in 1945, he also began work at Bell Laboratories. Equally committed to both Princeton and Bell Labs, Tukey chose to work concurrently at both institutions. He was also a consultant for many companies, such as Merck and Company, Xerox Corporation, and the Educational Testing Service, and was a frequent advisor to the government for such programs as the US Census. From 1960 to 1980 he led the statistical component of NBC's election night projections. Among other projects Tukey analyzed Alfred Kinsey's research and examined data on ozone depletion. Tukey made many important contributions to the field of statistics, such as work in time series analysis, exploratory data analysis, and multiple comparisons. Through his work, Tukey developed statistical applications including the Box-and-Whisker Plot, the Stem-and-Leaf Diagram, Cooley-Tukey Fast Fourier Transforms, Tukey's Paired Comparisons and citation and permutated indices. Tukey's influence extends beyond statistics to everyday language: he was the first to use the word "software" in print and coined words such as "bit" and "linear programming." A prolific writer, John W. Tukey penned more than 500 technical papers and reports and published, among numerous other works. His collected papers amount to eight volumes of work. The Tukey Papers provides a comprehensive perspective into Tukey's professional activities from his days as a graduate student until his death in 2000. Among the material is his correspondence and his published and unpublished works. There is abundant material from Tukey's long careers at Bell Laboratories and Princeton University, including extensive lecture notes and syllabi. Also included are copious materials relating to his professional activities with such agencies as the National Research Council, the Army Records Office, Xerox PARC, Merck and Company, the President's Science Advisory Committee, and the National Academy of Sciences.

Leonard Carmichael was a psychologist whose most significant contributions were made in the fields of child psychology and biopsychology. Educated at Tufts and Harvard, he taught at Princeton, Brown, and Rochester, later returning to Tufts to serve as its President from 1938-1952. An outstanding administrator, Carmichael served as executive officer for the Smithsonian Institute from 1952-1964, and was subsequently vice president for research and exploration at the National Geographic Society. In his later years, he served as President of the American Philosophical Society from 1970-1973. This large and varied collection reflects the entire range of Carmichael's prolific career. It includes a variety of types of records, including correspondence, committee reports and records, long series of articles and speeches, drafts of papers and books, and pocket notebooks. All phases of his professional life are covered, from his years in academia, to his time at the Smithsonian Institute and the National Geographic Society, as well as his involvement in a large number of professional organizations.

A gifted mathematician, Polish-born Stanislaw Ulam made contributions to set theory, topology, mathematical logic, and number theory, but is most widely remembered for his work in fostering the technical development of thermonuclear weapons. He was associated with Los Alamos Scientific Laboratories for most of the years between 1943 and 1965, and thereafter with the University of Colorado. These papers include personal and professional correspondence, manuscripts of both published and unpublished works, and memorabilia.

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.