Robert B. Austin was a reference librarian and Head of NLM's Circulation and Book Custody Section. Initially begun in 1946 as a project to identify Americana in NLM's collections, it was expanded in the 1950s to include comprehensive information covering the holdings of libraries across the country. The preliminary list, produced in 1958 was amended and augmented before being published in 1961.
From the guide to the Robert B. Austin Early American Medical Imprints: checklist, page proofs, and other draft materials, 1951-1961, (History of Medicine Division. National Library of Medicine)