Includes materials that were kept by Dirac in Tallahassee as well as the collection that was kept on loan at the Library of Churchill College, Cambridge, UK. Includes correspondence and rough notes showing the developing history of quantum mechanics from the 1920s to the 1930s. Also contains professional and some personal correspondence, manuscripts and reprints of published papers. Manuscripts of books, speeches, lectures, and course notes. There are numerous handwritten calculations. The collection includes correspondence, photographs of Dirac, his family and friends; audio and video tapes of Dirac are also included. Correspondents include: Niels Bohr, Max Born, Peter Kapitsa, Erwin Schrd̲inger, Ralph Fowler, Werner Heisenberg, Wolfgang Pauli, Homi Bhabha, and Eugene Wigner.