Chicago Manual of Style
The Chicago Manual of Style is a comprehensive style guide published by the University of Chicago Press, widely used in book publishing, academic writing and long-form journalism.
Also known as:
Chicago style, CMOS, CMS
What is Chicago Manual of Style?
Chicago Manual of Style, often shortened to Chicago style or CMOS, is the reference book that sets editorial conventions for book publishers, scholarly journals and many magazine publications. It covers grammar, punctuation, citation formats, manuscript preparation and document design. For example, Chicago style uses the Oxford comma and offers two citation systems: notes and bibliography for humanities work, or author-date for sciences and social sciences.
Why does Chicago Manual of Style matter?
Chicago style matters because it is the default rulebook for long-form writing where precision and source attribution are critical. Academic publishers, university presses and many magazines follow it closely, so authors who learn Chicago can work across those markets without retraining. For teams producing research reports, white papers or books, adopting Chicago brings editorial consistency that readers recognize as serious and well-sourced.
Examples of Chicago Manual of Style
Serial comma — Chicago uses the Oxford comma, so "fast, flexible, and affordable" keeps the final comma before "and."
Numbers — Chicago spells out whole numbers from zero through one hundred, then switches to figures, giving "ninety-nine chapters" but "150 pages."
Citations — Chicago offers two systems: notes and bibliography for humanities writing, or author-date for scientific fields.
