The Jeffrey Papers include biographical material, correspondence, research and lecture notes, teaching documents, and drafts of published and unpublished writings by Jeffrey and others. Series I comprises biographical information. Included in the correspondence series (Series II) are extensive exchanges with Jeffrey's close colleagues, teachers, friends, and collaborators such as Rudolf Carnap, Carl Gustav Hempel, and Brian Skyrms. Materials in the research series (Series III) range from sketchy outlines, typescripts and documents reflecting Jeffrey's collaborations with Carnap, to numerous grant proposals and projects that are indicative of Jeffrey's research interests at the time. Series IV focuses on Jeffrey's writings and publications including manuscript drafts, lecture notes, and his editorial work, which centers mainly on the publication of Hempel's
Selected Philosophical Essays. Series V covers material from Jeffrey's teaching activities, such as syllabi, teaching notes, reading lists, and exams. Series VI contains writings by others in form of unpublished drafts or annotated published pieces.