The 1911 eleventh edition was assembled with the management of American publisher Horace Everett Hooper. Hugh Chisholm, who had edited the previous edition, was appointed editor in chief, with Walter Alison Phillips as his principal assistant editor.
Originally, Hooper bought the rights to the 25-volume 9th edition and persuaded the British newspaper The Times to issue its reprint, with eleven additional volumes (35 volumes total) as the tenth edition, which was published in 1902. Hooper's association with The Times ceased in 1909, and he negotiated with the Cambridge University Press to publish the 29-volume eleventh edition. Though it is generally perceived as a quintessentially British work, the eleventh edition had substantial American influences, not only in the increased amount of American and Canadian content, but also in the efforts made to make it more popular. American marketing methods also assisted sales. Some 14% of the contributors (214 of 1507) were from North America, and a New York office was established to coordinate their work.
The initials of the encyclopedia's contributors appear at the end of selected articles or at the end of a section in the case of longer articles, such as that on China, and a key is given in each volume to these initials. Some articles were written by the best-known scholars of the time, such as Edmund Gosse, J. B. Bury, Algernon Charles Swinburne, John Muir, Peter Kropotkin, T. H. Huxley, James Hopwood Jeans and William Michael Rossetti. Among the then lesser-known contributors were some who would later become distinguished, such as Ernest Rutherford and Bertrand Russell. Many articles were carried over from the 9th edition, some with minimal updating. Some of the book-length articles were divided into smaller parts for easier reference, yet others much abridged. The best-known authors generally contributed only 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 encyclopædia 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' great maps as low quality reproductions.