Correspondence with Professor Gilbert Ryle, 1949-66, and Professor Dennis Grey, 1949-53 Box 5 Unit ID: 36
Correspondence with Professor Maurice Mandelbaum, 1959-65, and Professor T. W. Bynun, 1968 Box 5 Unit ID: 40
Correspondence with Professor Richard Hare, Wolfgang Brezuka, Karl Popper, Gilbert Ryle and Julian Huxley, 1948-84 Box 5 Unit ID: 34 Date: 1948-84
Correspondence with publishers regarding One hundred years of philosophy, 1952-68 Box 9 Unit ID: 4 Date: 1952-68
Correspondence with publishers regarding Philosophical reasoning, 1961-69 Box 10 Unit ID: 10 Date: 1961-69