Included is both family and business correspondence. The family's letters give information on Robert Cadell's early career in the Clyde Iron Company, the court-martial of Charles Cadell in 1831, the financial support given by Robert Cadell to his family and others, and his purchase of Ratho House in 1844. On the business side, there is correspondence with Archibald Constable and the Ballantynes (some of which is related to MSS.789-802), Cadell's financial problems, the illness and death of Sir Walter Scott and the printing, illustration and publication of his works.