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.