After he had left Oxford, Hirst edited political and economic books for Harper's, including one on Toryism by F. E. Smith and one on Socialism by R. C. K. Ensor. Another was his compilation of extracts from Richard Cobden, John Bright, Joseph Hume, W. J. Fox, William Molesworth, Thomas Farrer and others, titled "Free Trade and Other Fundamental Doctrines of the Manchester School". In 1904 Morley asked Hirst to write a biography of Adam Smith for his "English Men of Letters" series. During the next two years he wrote "The Arbiter in Council", an imaginary dialogue in which the Arbiter, an old Cobdenite Radical, discusses the issues of war and peace. Morley recommended it to Macmillan and it was published anonymously but the authorship came to be known.