The papers of Barbara McLain contain personal correspondence and other communications related to books and book collecting. McLain appears to have been an avid collector of twentieth century literature and first editions, especially those of Christopher Morley and Ernest Hemingway. The papers are arranged in two series: I. Correspondence, 1928-1956, and II. Other Papers, 1919-1970.

There is extensive correspondence from Ben Abramson, owner of The Argus Book Shop, sent to Barbara McLain, first from Chicago and then New York, between 1928 and 1953. The discussions in these letters are wide-ranging, beginning with formal reading suggestions and growing to include more personal topics, such as a vacation Abramson took to Mexico and his thoughts on World War II. The correspondence breaks off abruptly in 1953. There is one folder of drafts of letters sent from McLain to Abramson, but these letters are much fewer in number than Abramson's.

Catalogs, book announcements, and invoices that document McLain's book buying are also present in the collection. The catalogs are all from The Argus Book Shop and Argus Books, but there are announcements and invoices from a number of other book sellers as well, including James F. Drake, Inc. of New York, and the Artemisia Book Shop in San Diego. Several folders of personal and family papers also show McLain's interest in books and book collecting, with lists of books she read and articles on book collecting techniques.