Encyclopædia Britannica it is scarcely used, and reviewers have recommended that it be dropped from the encyclopaedia. The also has color transparencies of human anatomy and several appendices listing the staff members, advisors, and contributors to all three parts of the Britannica. Taken together, the and comprise roughly 40 million words and 24,000 images. The two-volume index has 2,350 pages, listing the 228,274 topics covered in the "Britannica", together with 474,675 subentries under those topics. The "Britannica" generally prefers British spelling over American; for example, it uses "colour" (not "color"), "centre" (not "center"), and "encyclopaedia" (not "encyclopedia"). However, there are exceptions to
Collier's Encyclopedia about two-fifths of the pages. Bibliographies are found in the last volume which also contains the 450,000 entry essential index. An annual "Collier's Year Book" was also published. In 1998 Microsoft bought the rights to Collier's electronic version and incorporated it into its "Encarta" electronic encyclopedia. Atlas Editions (formerly Collier Newfield) retained the rights to publish the encyclopedia in book form, though since then, Collier's has ceased to be in print. A well-known comparison is that of Kenneth Kister, who gave a qualitative and quantitative comparison of "Collier's Encyclopedia" with the "Encyclopædia Britannica" and the "Encyclopedia Americana". For the "quantitative"