 The articles describing World War I and the political changes brought about by it took up a large portion of the supplement, but articles on such things as radio (still called wireless telephony) are informative.The editor of the supplement was Hugh Chisholm, who also had been the main editor of the eleventh edition, as well as the 1902 eleven-volume supplement to the ninth edition, known as the tenth edition.Horace Hooper died in 1922, a few weeks after the publication of the twelfth edition.