U.S. Army officer. Correspondence (1929–1954) concerning McLain’s personal and business affairs; orders, memoranda, reports (1920–1937), and correspondence (1939–1940) from McLain’s service with the Oklahoma National Guard; speeches (1947–1954) made by McLain as chief of information for the U.S. Army and as a member of the National Security Training Commission; a typescript account (n.d.) by McLain of his participation as commander of the Forty-fifth Division artillery in the Allied invasion of Sicily during World War II; and a typescript account (n.d) by McLain of the Forty-fifth Division artillery’s role in the Battle of the Aisne (1918) in World War I. [This collection has a restriction. See finding aid for details.]