The Newberry Library's institutional records, records of the Walter L. Newberry estate, personal papers of staff members and trustees, photographs, and publications that document the establishment and operation of the library.

Beginning with Newberry estate trustees Blatchford and Bradley, individuals associated with the Newberry Library have conscientiously preserved the great majority of the institutional records documenting the Library's history. However, over the years no coordinated effort to organize and describe the records had been undertaken, making much of the extensive archive inaccessible except through the intervention of knowledgeable staff members.

In 1990, the Newberry Library received a grant from the National Historical Publications and Records Commission to establish an archives program for the Library's institutional records. The primary objective of this project was to provide an overall structure for and descriptive access to the Library's historically and administratively valuable records.

Several preliminary documents paved the way for the actual arrangement and description of the archives. The Newberry Library Archives was formally established through a Trustee-approved Archives and Records Policy Statement which defined the archives' scope, responsibility, authority, and governance. To facilitate systematic and timely transfer of office records to the archives, the project staff prepared a Records Disposition Schedule Handbook containing series level record group descriptions and retention recommendations arranged in record groups and subgroups paralleling the Newberry's organizational structure.

Based in part on this classification system, the Newberry Library Archives are organized in sixteen record groups representing the Library's larger divisions and departments; special formats such as publications, artifacts, and audiovisual materials; and outside source materials (e.g. newspaper clippings). The record groups are further divided into subgroups representing smaller departments or sections and staff offices within divisions; or types of materials (e.g. photographs). Within each subgroup, or office of origin, the record series identify and describe individual office files.

All record groups, subgroups, and series are assigned numbers, which when placed together constitute a unique identification number. For example, 02/01/20 would represent Board of Trustees (record group), Office of the Board of Trustees (subgroup), Annual Reports (series). A complete classification guide to the Newberry Library Archives lists by number and title all record groups, subgroups, and series held in or designated for eventual transfer to the archives. In the classification guide, the 142 processed record series can be identified by the presence of inclusive dates following the title. Marked with asterisks, unprocessed files have for the most part been transferred to the archives and are shelved in classification guide order.

Arranged in classification number order, the present guide contains narrative record group, subgroup, and series descriptions, and box and folder lists for processed records only. The 142 processed record series comprise virtually all of the pre-1940 or historical files and records transferred to the Archives to the date of processing.