The collection consists of papers of Papadaki. Included is correspondence (1922-1990) with many architects from the United States, Europe, Greece, and Brazil, such as Jorge Amado, Charles S. Ascher, Leonidas Cheferrino, Serge Chermayeff, Lucio Costa, Marcel Gautherot, Matila Ghyka, Siegfried Giedion, Walter Gropius, Jean Helion, Le Corbusier (Charles Edouard Jeanneret), Lazlo Moholy-Nagy, Oscar Niemeyer, Amedee Ozenfant, Eugene C. Petit, Alberto Sartoris, Jose Sert, and Frank Lloyd Wright. There is also correspondence with organizations, artists, friends, and family, including the Architectural Forum, Alexander Calder, John Dale, Macmillan Company, the Museum of Modern Art (N.Y.), CIAM, Michales Tompros, and Henry Yannilos, and a lengthy correspondence (1939-1979) with his sisters, Maria and Photeine, in Greece.

Works include manuscripts and photographs for his book Le Corbusier, Architect, Painter, Writer, an unpublished work entitled The Compass and the Unicorn: Modulations of the Inhabited Space (circa 1962), various articles, book reviews, and two compilations of poetry, "Les Jeux et Les Jours" and "De Trebizonde a Metaponte et au Dela" (1972).

Subject files contain correspondence, photographs, articles, notes, drawings, and printed matter relating to the development of Brasilia, his work on various projects for the CIAM, and plans for a Le Corbusier exhibition; drawings, notes, and manuscripts of his research with Le Corbusier and Le Corbusier's own writings for Le Modular (1954), a system of harmonious measurement for architects and mechanics (the papers also include an original, hand-drawn, colored, and signed "modulor" tape by Le Corbusier); covers and layouts for the magazines Plus and Progressive Architecture; plans and articles on prefabricated houses and mountain shelters; and many plans, blueprints, drawings, elevations, and photographs for other architectural projects, including the New York World's Fair pavilion, the New York International Airport, a seaside villa near Athens, office buildings on Park Avenue, exhibitions for IBEC and UNESCO, designs and photographs (circa 1981) for the Museum of Modern Art on Andros Island, Greece, and houses and commercial buildings in Greece, Brazil, and the United States.

Also present are blueprints and plans (1940s) for Papadaki's home in Washington, Connecticut, original drawings and works of abstract art, furniture designs by Papadaki and Le Corbusier, photographs of Papadaki and Le Corbusier, including a photograph of Le Corbusier with Albert Einstein, diplomas and award certificates, printed matter, including copies of the Brazilian newspaper Para Todos and publications in Greek, and articles or designs of other people such as Siegfried Giedion, Fernand Leger, Vladimir Bodiansky, Alberto Sartoris, and Andre Wogenscky.