The American Institute for Christianity was incorporated in 1923 to enable the planning and production of a proposed 12 volume American Encyclopaedia of Christianity. Denominational councilors, writers, editors and supporters were contacted across the USA. The Institute was unable to attract adequate funding to produce the Encyclopaedia. The bulk of the Records consist of planning documents and correspondence.

Includes letters, documents, pamphlets, clippings and ephemera collected by Rockwell and relating to his teaching, research, and library careers. Roll books, lecture materials, student papers related to his teaching on Congregational history and polity, and his work in the Union Theological Seminary library.

Includes letters, documents, pamphlets, and many manuscript notes by Rockwell.