Style Guides: Chicago, APA, MLA

Chances are that if you’re publishing a book or submitting an academic paper, grant proposal, or any other scientific written work, you’ve been instructed to follow a style guide. Contrary to widespread belief, style guides are not just about proper citing  and referencing of source material. If that were the case, we would be at a loss to explain why the Chicago Manual of Style, now in its 17th edition, is a massive 1013-page volume (with a 129-page index to boot).

In academic writing, presentation is as crucial as content. Following the preferred style and reference guidelines specific to each discipline is part of the conventions of academic discourse and crucial for any researcher wishing to be taken seriously and have their work evaluated on its own merits. (Alas, there are no bonus points for doing things your own way.)

That’s what a style guide is for: organizing and presenting your work. Style guides are reference books that lay down the rules for writing, grammar and syntax, correct word usage, appropriate use of headings, formatting of your work and references, and many other important aspects, such as how to deal with abbreviations, spelling, punctuation, and typography.

In other words, a style guide provides a consistent set of standards for you to follow, which tend to be specific to your field of study. This, in turn, helps you convey your message to your audience.

Chicago, APA, and MLA are the three main style guides used to properly format academic written work. Regardless of which style you are required to follow, it is crucial that you use the most recent version of the guidelines to ensure your publication is as accurate as it can be.


  • Chicago style (CMOS)The Chicago Manual of Style  has been published and periodically reviewed by the University of Chicago Press since 1906. Commonly used in both trade and academic publishing, CMOS is the preferred style for, among others,  Business, History, and the Fine Arts.   It includes two systems for citation: a notes and bibliography system and an author-date system. The most recent CMOS guidelines can be found in the 17th edition of the manual.


  • APA style: Published by the American Psychological Association since 1952, the APA Publication Manual is now in its 7th edition. Used by hundreds of scientific journals, it’s the preferred style guide in Education, Psychology, Social and Behavioral Sciences.


  • MLA style: The MLA Style Manual and Guide to Scholarly Publishing is the standard style guide for the Humanities, languages and literature in particular. It was first published by the Modern Language Association in 1985 and went out of print in 2016. The most recent guidelines can be found in the 9th  edition of its abridged version,  the MLA Handbook