The economic historian Charles Ryle Fay (1884-1961) was a staunch advocate of workers’ and women’s rights, and also became one of the leading British machine gunners during World War One. As an economist his associates included Alfred Marshall, JM Keynes and Sir Austin Robinson; as a historian he taught at Cambridge University for almost thirty years and in Canada in the 1920s, writing twenty books, including idiosyncratic works defying biographical norms – on his heroes William Huskisson and Adam Smith. What does his life tell us about the differences between making history and writing about it?