A collection of letters to Lord Acton, nearly all relating to the Cambridge Modern History. The principal correspondent is his co-editor W.A.J. Archbold; the remainder are for the most part potential or actual contributors to the History, replying to Acton's invitations to take part or writing about their contributions. Appended are a further letter of A.W. Ward, 1914, and one of Herbert Butterfield, 1964, relating to the collection, and a few miscellaneous papers. 291 items.