This series consists primarily of correspondence received by Nicolson from friends and colleagues, such as Maurice Baring (1929-1943), Clive Bell (1924-1929), Bernard Berenson (1938, 1946, 1950), Guy Burgess (1950, 1958-1962), Anthony Eden, Earl of Avon (1921, 1935, 1937-1938, 1943-1946), Sir John Gielgud (1938), John Gunther (1960), Francis King (1951, 1953-1954, 1958-1960), Alan Lascelles (1940, 1960, 1962), Charles A. Lindbergh (1936), André Maurois (1934, 1940), Paul Morand (1934), Raymond Mortimer (1925, 1953, 1957-1961), Robert Vansittart (1938, 1940) and H. G. Wells (1930, 1939). The majority of correspondents are represented by one to three letters; also present are a few letters by Nicolson to these individuals. There is a large selection of letters by Nicolson to Richard Rumbold (1934-1935, 1937-1949, 1951-1960), as well as other correspondence associated with Rumbold (1937, 1961) and a photograph of Rumbold in military uniform. Furthermore, there is a small selection of miscellanea that includes two unidentified letters and a menu signed by the British delegation to the Paris Peace Conference in 1919.

This series consists of correspondence by and to "Vita" (Victoria) Sackville-West, as well as correspondence by Frederick Temple Blackwood, Marquis of Dufferin and Ava and Henry Charles Keith Petty-Fitzmaurice, Marquess of Lansdowne.

This series consists of the correspondence received by Mujica Láinez, as well as a few manuscripts by him, and several manuscripts by others. The series is arranged alphabetically. Included at the front of the series is a chronology of his career and life, written by his daughter (Ana Mujica) and daughter-in-law (Susana Rodríguez de Mujica Láinez). There is substantial correspondence from both Silvina and Victoria Ocampo; his close friend, and novelist Marta Lynch; his friend, and later, biographer, Oscar Hermes Villordo; as well as his Argentinian-Spanish friend Marcos Ricardo Barnatán, and his Spanish friends Guillermo Carnero and Luis Antonio de Villena. There is an undated, four-page letter to Mujica Láinez from Chilean poet Gabriela Mistral, written while she was staying in Buenos Aires. The series is notable for the range of dates which the correspondence spans, 1927 to 1984, and for its varied documents which portray the Argentinian literary scene, primarily in the decades of the 1940s-1970s.

Consists of family correspondence, divided into those of general family members and those of Manuel Mujica Láinez.

Consists of the writings, correspondence, photographs, and scrapbooks of Louise Selina Bonynge Maxwell.

Consists of bound volumes (versebook from 1824, gift of John Pascoe Grenfell to Algernon Grenfell; Arabic prayer book, 1894-1895), documents, and unidentified papers.

This series contains materials related to Félix Candela's professional work as an architect, structural engineer, and master builder, both for his own company and as a technical advisor for other firms. Included are many black-and-white and color photographs, slides, negatives, and transparencies showing Candela's finished structures and works under construction, along with some architectural drawings, sketches, and designs, and a smaller quantity of maps, calculations, and project files pertaining to specific buildings. Rather than serving as traditional architectural project files, the materials in this series document the design, construction, and completed forms of many of Candela's buildings, primarily through photographs, and secondarily, through Candela's architectural drawings and specifications, which provide insight into his design process. This series includes an original run of conceptual files on specific buildings, arranged by architectural feature or theme, that contain both photographic materials and architectural drawings. Also present is a group of slides and negatives of Candela's work, along with microfilms of technical articles related to his projects, that he organized separately by medium, and additionally, a group of Candela's photographic materials, which were later arranged based on their use for research and publication in a book by Maria Garlock and David Billington, Félix Candela: Engineer, Builder, Structural Artist (Princeton University Art Museum, 2008). These divisions were preserved in order to maintain contextual evidence regarding use and original organization. Researchers looking for photographs of a specific building should note that relevant materials may therefore be present in all three subseries.