Papers, 1840-1972, of and relating to Karl Pearson, comprising personal and family papers, 1844-1937 (Ref: 1-45); lectures and lecture notes, 1874-1972 (Ref: 46-84); papers relating to literary and scientific work [1870]-1936 (Ref: 85-229); papers relating to the history of the Department of Applied Statistics, University College London, 1895-1936 (Ref: 230-258); papers relating to the work of the Department of Statistics and of Pearson's colleagues, 1895-1962 (Ref: 267-346); papers relating to the journal Biometrika, 1900-1954 (Ref: 347-570); papers relating to Pearson's The life, letters and labours of Francis Galton, 1840-1931 (Ref: 571-598); papers relating to Pearson's wartime research (1914-1918), 1905-1923 (Ref: 599-612); acquired papers, 1842-1923 (Ref: 613-623); general correspondence [1843-1972] (Ref: 624-933). The collection also includes papers of Walter Frank Raphael Weldon (Jodrell Professor of Zoology and Comparative Anatomy at University College London), 1860-1935 (Ref: 259-266).

Papers of John Burdon Sanderson Haldane, comprising scientific notes and papers; correspondence with publishers; scientific correspondence; general correspondence; University College London departmental files, wartime committees, and other societies; and some personal financial and domestic papers. There are also some papers of Charlotte Haldane which consist of correspondence, including letters about Women Today magazine, and bills.

Papers relating to the foundation and early days of the journal Biometrika, 1901-1916; papers relating to the Biometrika Trust, 1935.