The collection comprises:
- Notebooks of Piaggio from his time as a student at Cambridge University containing hand-written notes relating to mathematics, astronomy, grammar etc., 1902-1907 (MS 621/1).
- Notebook containing notes made on works written by three other writers on mathematics, undated, after 1921 (MS 621/2).
- Loose manuscript mathematical notes made by Piaggio as well as notes made from works by other mathematicians, undated, c. 1913-1950 (MS 621/3).
- Correspondence, 1912-1949 (MS 621/4).
- Testimonials, 1908-1913 (MS 621/5).
- Off-prints of 'The Conformal Transformation' by H. Piaggio and M.N. Strain, 1947 (MS 621/1/6).
- Newspaper cuttings, undated c. 1936 (MS 621/7).
- Postcards, mostly of historic York, undated, c.1910 (MS 621/8).
- Off-prints of mathematical works by authors other than Piaggio, 1910-1954 (MS 621/9).
- Mathematics examination papers, 1900-1950 (MS 621/10).
- Student notebook of E.J.G. Titterington at Perse Grammar School, Cambridge, October 1901 (MS 621/11).