The Chicago Manual of Style

The Chicago Manual of Style (abbreviated in writing as CMS or CMOS [the version used on its website], or, by some writers as Chicago) is a style guide for American English published since 1906 by the University of Chicago Press. Its sixteen editions have prescribed writing and citation styles widely used in publishing. It is "one of the most widely used and respected style guides in the United States."CMOS deals with aspects of editorial practice, from American English grammar and use for document preparation.

The Chicago Manual of Style is published in hardcover and online. The online edition includes the searchable text of both the fifteenth and sixteenth—its most recent—editions with features such as tools for editors, a citation guide summary, and searchable access to a Q&A, where University of Chicago Press editors answer readers' style questions. The Chicago Manual of Style also discusses the parts of a book and the editing process. An annual subscription is required for access to the online content of the Manual. (Access to the Q&A, however, is free, as well as to various editing tools.)

The Chicago Manual of Style is used in some social science publications and most historical journals. It remains the basis for the Style Guide of the American Anthropological Association and the Style Sheet for the Organization of American Historians. Many small publishers throughout the world adopt it as their style.

The Chicago Manual of Style includes chapters relevant to publishers of books and journals. It is used widely by academic and some trade publishers, as well as editors and authors who are required by those publishers to follow it. Kate L. Turabian's A Manual for Writers of Research Papers, Theses, and Dissertations is based on the Manual.

Chicago style offers writers a choice of several different formats. It allows the mixing of formats, provided that the result is clear and consistent. For instance, the fifteenth edition of The Chicago Manual of Style permits the use of both in-text citation systems and/or footnotes or endnotes, including use of "content notes"; it gives information about in-text citation by page number (such as MLA style) or by year of publication (like APA style); it even provides for variations in styles of footnotes and endnotes, depending on whether the paper includes a full bibliography at the end.

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