The collection comprises copies of printed material, 1907-1984, including history of Perry and Co, builders and contractors, with list of completed building projects, photographs of founders, and notes on the company's projects including St Thomas's Hospital, London, Tower Bridge and numerous Underground railway stations including Oxford Circus and Piccadilly Circus, [1907]; copy of article on the Perry & Co employee, Sir Herbert Henry Bartlett, by Sir Basil Bartlett, printed in David Jeremy ed., Dictionary of business biography (London, 1984); manuscript pedigree describing the relationship between the Robinson and Bartlett families, to whom the donor was related, [2000].

Collection comprises correspondence with Philip Hammersley Leathes, manuscript papers, diaries, devotionals, dictionaries and pedigree rolls, title deeds and indentures, printed books and pamphlets, catalogues and the manuscripts of the architect, John Carter, [1350-1863]. Notably including correspondence from George Nayler of the College of Arms and Nicholas Carlisle, Secretary of the Society of Antiquaries, relating to publications of the Society, discoveries of antique brass plate, and the exchange of manuscripts between antiquaries, [1790-1838]; loose manuscript papers collected by Leathes, describing ornamentation in early printed devotionals, a fictional narrative entitled 'The amorous Jill: A tale', narrative of the Lisbon earthquake of 1755, notes relating to the observation of comets, including the comet of 1811, copies of charters of the reigns of Edward IV and Henry VII, papers relating to the Portland Vase, British Museum, fragments describing inscription on newly discovered brass plate, 1747-1829; pedigree rolls tracing the lineage of the English Crown, [1450, 1762]; manuscript volumes including collection of biblical extracts, liturgical handbook, autograph book with colour illustrations, antiquarian ephemera such as funeral memorials, armorials and the creation of nobles, volume by Francis Harrison entitled, 'The elements of navigation' with colour charts, tables and illustrations, dictionaries of Celtic and Saxon words, notes on the teaching of mathematics, commonplace book drawing on ancient and modern authors, manuscript diary including progress of architectural tour of Europe; title deeds and indentures for families in Nottingham, Southampton, London and Hungerford, residency certificates in Buckinghamshire and Northamptonshire, 1650-1751; printed books and pamphlets on the subjects of antiquarianism, genealogy and architecture, 1778-1853; manuscripts of John Carter, architect, acquired at his death in 1817 by his executor, Leathes, notably including autobiographical notebooks by Carter describing architectural subjects and tours, commonplace book, correspondence with Leathes, loose notes on linguistics and the ships of the Russia Company, obituaries of Carter and sale catalogue from his estate, 1700-1818; manuscript catalogues and display captions relating to the Leathes' papers, King's College London, 1819, 1837.

Four letters, 1913-1920, to George Charles Williamson, author of Lady Anne Clifford, Countess of Dorset, Pembroke and Montgomery, 1590-1676: her life, letters and work (T Wilson & Son, Kendal, 1922), mainly concerning Round's opinion on the relevance of a volume containing an Elizabethan peerage to the Clifford peerage claim.

Papers of and relating to Evelyn Underhill, 1874-1997 and undated, comprising personal correspondence of and concerning Underhill, 1888-1969 and undated, the correspondents including Baron Friedrich von Hugel (three letters, 1911-1916), Underhill's husband Hubert Stuart Moore (117 letters from Underhill to Moore, 1890-1912 and undated, and 30 letters from Moore to Underhill, 1898-1906 and undated), Rabindranath Tagore (typed transcripts of 10 letters from Underhill to Tagore, 1913-1914), and members of the Underhill family, the subjects ranging from Catholicism, travels in Italy, Switzerland and France, publications and lectures, spiritual matters and advice, mysticism, health, and World War Two; correspondence, 1907-[1954], with various publishers concerning Underhill's publications (some posthumous) and broadcasts, including copyright, costs, sales and royalties; manuscripts and typescripts containing proposed holiday itineraries and recording Underhill's impressions while travelling in Italy, Switzerland and France, 1898-1899, 1901-1907; poetry, 1917-1923 and undated, including some work which was published; a speech at King's College London on being elected a Fellow, 1927; an article on 'The Fountain of Life: an iconographical study', published in 1910; material relating to spiritual development, 1921-1939, mainly under the guidance of Baron Friedrich Von Hugel and including transcripts of his letters, 1921-1924, and other items on spiritual advice, confessions, goals and progress; papers relating to retreats and religious writings, 1924-1932 and undated, including notebooks and texts of addresses; printed material by and concerning Underhill, 1926-1941, 1990, including some of her publications; press cuttings, 1891-1949, mainly reviews of Underhill's work but also including early published pieces; sketchbooks and drawings, 1892-1911 and undated, including sketches and watercolours of marine scenes in Britain, ecclesiastical subjects, and Italian and French architecture; photographs, c1925-c1930s and undated, including a photograph and negatives of Underhill (one at Pleshey), a portrait of Baron Von Hugel, marine views, and views of French and Italian castles and towns; material relating to the Underhill family, 1874-1940, including the marriage certificate of Evelyn Underhill's parents, 1874, a family tree, c1891, a copy of Evelyn Underhill's will, 1940, and details of books in Dr Williams's Library, London, which originated from Underhill's library; obituaries of and articles about Underhill, 1941-1997, including theses, bibliographies, memoirs, biographical material and reflections on her work; newsletters of the Evelyn Underhill Association, 1992-1997.