These papers, which concern mostly Kridl's years in the United States, consist of correspondence, manuscripts, documents, photographs, and printed materials. Among the correspondents are Oskar Kalecki, Roman Jakobson, Hans Kohn, Czesław Miłosz, Leszak Serafinowicz (Jan Lechoʹn), Kazimierz Wierzyʹnski, Jʹosef Wittlin, and Florian Zaniecki; there are one or two items each from Vladimir Nabokov, Harlow Shapley, and Antoni Slonimski. The manuscripts include lectures and articles by Kridl; there are also personal and family documents. There are about 100 photographs from Warsaw during the 1944 uprising and immediately after World War II. Printed materials include copies of books by Kridl.