Charles Adam Platt (1861-1933) was an American architect and landscape designer. Although best remembered today for his landscape and country house designs, he was also nationally known for his etchings, landscape paintings, commercial architecture, and institutional projects. He was largely self-taught in each of these disciplines, building his success on his ability to reconceive the classical tradition in architecture for the needs and desires of his wealthy, powerful clients. This collection contains materials related to Platt's personal and professional lives, the bulk originating from Platt's office in the form of project drawings, photographs, and records documenting architectural projects from 1901-1933.

This collection primarily contains architectural drawings, correspondence, business records, and a small number of photographs related to the projects of Emery Roth & Sons and its subsidiary entities. A large portion of the entities are represented only in the Office Records series and are identified as such. Some projects on which Emery Roth & Sons acted as architect of record are not represented in this collection, most notably the Twin Towers of the World Trade Center.

This collection contains architectural photographs, drawings and records related to the architectural projects and designs of Warren and Wetmore, principally in the United States, but also representing commissions in Canada, Cuba, and Puerto Rico. Unfortunately, the bulk of architectural drawings produced by the firm are no longer extant. Additionally, it holds a variety of photographs and other records used as reference materials in the course of Warren and Wetmore's professional work. Lastly, a small group of student and personal papers and photographs from Whitney Warren completes the collection.