Chicago style is a citation and formatting style you may encounter in your academic career. Any piece of academic writing can use Chicago style, from a one-page paper to a full-length book. It is used by most historical journals and some social science publications. If you are writing a paper for a history class, it is likely your professor will ask you to write in Chicago style.
The Chicago Manual
The Chicago Manual of Style (abbreviated in writing as Chicago style, CMS, or CMOS) is a style guide for American English published since 1906 by the University of Chicago Press. Its sixteen editions have specified writing and citation styles widely used in publishing. Chicago style deals with many aspects of editorial practice. 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 Turabian Manual
"Turabian style" is named after the book's original author, Kate L. Turabian, who developed it for the University of Chicago. Except for a few minor differences, Turabian style is the same as Chicago style. However, while Chicago style focuses on providing guidelines for publishing in general, Turabian's Manual for Writers of Research Papers, Theses, and Dissertations focuses on providing guidelines for student papers, theses, and dissertations.
The Purpose of Chicago/Turabian Style
Chicago/Turabian style offers writers a choice of several different formats, because it is used in a wide variety of academic disciplines. It allows the mixing of formats, provided that the result is clear and consistent.
The most recent edition of The Chicago Manual of Style permits the use of both in-text citation systems ("Author–Date" style, which is usually used in the social sciences) or footnotes and endnotes (this is called "Notes and bibliography" style, which is usually used in the humanities).
Grammar and Formatting
Chicago style includes many basic grammatical rules. For example, Chicago style does use the Oxford comma, which some other citation styles (e.g., AP style) do not. Other examples include rules about what punctuation should be included inside a quotation and when to use what type of dash. For instance, Author–Date citations are usually placed just inside a mark of punctuation.
Citations
As mentioned above, the most recent editions of The Chicago Manual of Style permit the use of either in-text citation systems or footnotes and endnotes. It can give information about in-text citation by page number or by year of publication; it even provides for variations in styles of footnotes and endnotes, depending on whether the paper includes a full bibliography at the end.