a single article or part of an article. Most of the work was done by journalists, British Museum scholars and other scholars. The 1911 edition was the first edition of the encyclopaedia to include more than just a handful of female contributors, with 34 women contributing articles to the edition. The eleventh edition introduced a number of changes of the format of the Britannica. It was the first to be published complete, instead of the previous method of volumes being released as they were ready. The print type was kept in galley proofs and subject to continual updating until publication. It was the first edition of Britannica to be issued with a comprehensive index volume in which was added a categorical index, where like topics were listed. It was the first not to include long treatise-length articles. Even though the overall length of the work was about the same as that of its predecessor, the number of articles had increased from 17,000 to 40,000. It was also the first edition of Britannica to include biographies of living people. Sixteen maps of the famous 9th edition of Stielers Handatlas were exclusively translated to English, converted to imperial units, printed in Gotha, Germany, by Justus Perthes and became part this edition. Later editions only included Perthes' maps as low quality reproductions. According to Coleman and Simmons, the content of the encyclopaedia was distributed as follows: Hooper sold the rights to Sears, Roebuck and Company of Chicago in 1920, completing the Britannicas transition to becoming a substantially American publication. In 1922, an additional three volumes (also edited by Hugh Chisholm) were published, covering the events of the intervening years, including World War I. These, together with a reprint of the eleventh edition, formed the twelfth edition of the work. A similar thirteenth edition, consisting of three volumes plus a reprint of the twelfth edition, was published in 1926. The London editor was J.L. Garvin, as Chisholm had died. The twelfth and thirteenth editions were closely related to the eleventh edition and shared much of the same content. However, it became increasingly apparent that a more thorough update of the work was required. The fourteenth edition, published in 1929, was considerably revised, with much text eliminated or abridged to make room for new topics. Nevertheless, the eleventh edition was the basis of every later version of the Encyclopædia Britannica until the completely new fifteenth