There is an index of correspondents.
Researchers use microfiche copies of the originals.
These letterbooks contain copies of handwritten or typed correspondence sent by John D. Rockefeller, John D. Rockefeller, Jr. or office staff on their behalf. Corresponding incoming letters may be found in the Correspondence series or in the John D. Rockefeller series in Record Group 2 . Subjects documented in the letterbooks include the individual and cooperative business endeavors of JDR and JDR Jr., their charitable and philanthropic activities, and the planning and management of Kykuit, the family's home in Pocantico Hills, New York. An index to the letterbooks has been compiled and is available at the Archive Center. Libraries, archives, and other interested parties, may contact the Rockefeller Archive Center about purchasing a copy.