A Polish-born mathematician who worked in symbolic logic, set theory and computation theory, Emil Leon Post received his doctorate from Columbia in 1920 for a dissertation proving the consistency of the propositional calculus described in Whitehead and Russell's Principia mathematica. He joined the faculty at City College of the City University of New York in 1932, where he remained until his death in 1954. Although illness continually interrupted Post's career, he made important contributions to the concepts of completeness and consistency and to recursive functions, foundational to modern computing theory. In 1936, he introduced the concept of a "Post machine," a sort of precursor to the von Neumann's notion of a program. The Post Papers consist of 8 linear feet of professional correspondence, research notes, and papers, to which have been added a small number of items of biographical interest.

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 These papers include personal and professional correspondence, manuscripts of both published and unpublished works, and memorabilia.