The Eugene M. K. Geiling Collection spans much of his medical career, particularly his work at the University of Chicago during the 1950s. The bulk of the material consists of correspondence with individuals, professional organizations, pharmaceutical companies, and educational institutions. Another series consists of Geiling's research materials for a biography of John Jacob Abel. The Abel materials include: research notes, transcripts, professional correspondence, excerpts from diaries, biographical and familial information, and reprints. Other materials in the Geiling papers include notes on the history of pharmacy and endocrinology, personal notebooks, and reprints.