 Constable was friends with Sir Walter Scott, who contributed the "Chivalry" article.To edit the supplement, Constable hired Macvey Napier, who recruited other eminent contributors such as Sir Humphry Davy, Jean-Baptiste Biot, John Stuart Mill, William Hazlitt, David Ricardo, and Thomas Malthus.Peter Mark Roget, compiler of the famous Roget's Thesaurus and a former secretary of the Royal Society, contributed the entry for physiology.