Featured here is a variety of material reflecting Carnap's research in the area of probability, specifically during his later years. Many of the drafts relate to articles later published in the work
Studies in Inductive Logic and Probability, such as the Carnap's manuscript "An Axiom System of Inductive Logic." This piece later evolved into "The Basic System of Inductive Logic, Part I," and "The Basic System of Inductive Logic, Part II," published in
Studies in Inductive Logic and Probability, Vol. I and II respectively. Included are also correspondence and manuscript drafts of other contributing authors such as Haim Gaifman, John Kemeny, Jürgen Humburg, and Richard Jeffrey, and discussion notes with Gordon Matthews and Lary Kuhns.