Correspondence, manuscripts, photographs, memorabilia, and printed materials concerning Berg's lifelong interest in and work for his alma mater. Berg served the University in many capacities such as vice-president and president of the Alumni Association of Columbia College, 1954-1958, and member of the board of directors of the Alumni Federation of Columbia University, 1946-1958. The correspondence deals chiefly with alumni affairs; some of the major correspondents include Harry J. Carman, Lawrence Chamberlain, Frank S. Hogan, Mr & Mrs Richard Rodgers, and Arthur Hays Sulzberger. Among the photographs are two signed by Dwight D. Eisenhower. Also included is a typescript memoir of Berg's three years as a student in the Columbia School of Law (1927). Berg collaborated with three other students on this memoir. Aaron Berg's correspondence with Dwight D. Eisenhower is at the Eisenhower Library. Also included are literary autographs and manuscripts purchased on the Aaron Berg Fund.

The collection contains correspondence with the authors, including contracts signed with authors as well as negotiations with the authors over various aspects of publishing their works; financial records documenting many aspects of the operation of Harper & Brothers, including royalties paid to authors, records of stock offerings and company reorganizations, and general ledgers which contain daily notes on all aspects of the operation of the business; book catalogues and trade lists; research materials collected by Eugene Exman for his history of Harper & Brothers; visual materials, from drawings and photographs of Harper's authors to colophon designs and an oil painting of the original Harper's building.