A properly capitalized reference list that is aligned with your style guide is a vital step in completing a polished paper. However, knowing how to capitalize some of the most common items in references, such as book titles, can be tricky because the rules vary among style guides.
Here, we’ll go over how to capitalize a book title according to the rules of three of the most common reference styles: the American Psychological Association (APA), the Modern Language Association (MLA), and the Chicago Manual of Style (CMOS), which is also referred to as Chicago or Turabian style. (If you’re in a rush, scroll down to the bottom to check out our quick reference list.)
Differences Between Sentence Case and Title Case
Before we begin walking through the different style guides, let’s go over the difference between the two general approaches to capitalizing titles: sentence case and title case.
Sentence Case
When capitalizing a book title using sentence case, only the first word of the title, the first word of the subtitle (if present), and any proper nouns should be capitalized. For example:
Title Case
Although there are some nuances among style guides, the general rule when using title case is to capitalize the first word of the title, the first word of the subtitle (if present), nouns, pronouns, verbs, adjectives, and adverbs. The three books above in title case would be:
APA
APA has a long-held tradition of using sentence case for books in reference lists. During the revisions of the latest version, the Publication Manual of the American Psychological Association, Seventh Edition, the main aim was to prioritize accessibility, and the style team decided that sentence case for book titles was more readable.
An added benefit of having book titles in sentence case is that they are easier to find because they stand out from the rest of the reference items. Remember, when using sentence case, only the first word of the title is capitalized unless it’s a proper noun. For example:
To learn more about using APA referencing, check out our APA Guide.
MLA
The MLA capitalization rules for book titles in references generally follow title case and specifically dictate that the first and last word of a title, the first word of a subtitle, nouns, pronouns, verbs, adverbs, adjectives, subordinating conjunctions, and principal words that follow a hyphen should all be capitalized. Articles, prepositions (regardless of length), coordinating conjunctions, to in infinitives, and the second word after a hyphen in a compound modifier should not be capitalized. These are a few examples of books following MLA’s capitalization rules:
One caveat in MLA referencing is that sources without a title, such as untitled essays or social media posts, should be quoted with the first few words of the text, and follow the same capitalization.
To learn more about using MLA Referencing, check out our MLA Guide.
CMOS
Although there are also several differences between CMOS references and other style guides, and even two different reference systems within CMOS itself, the capitalization rules for book titles are similar to MLA with a few additional directives. Their rules also follow title case and advise that the first word and the last word of a title and subtitle should be capitalized as well as all nouns, pronouns, verbs, adverbs, adjectives, subordinating conjunctions, and principal words that follow a hyphen.
Articles, prepositions (regardless of length), coordinating conjunctions, the word to in infinitives, and the second word after a hyphen in a compound modifier should not be capitalized. Additionally, the conjunctions and, but, for, or, and nor, and the word as should not be capitalized. A proper name that would be lowercase in text (e.g., Johann Wolfgang von Goethe) and the second part of a Latin species name should also not be capitalized. Here are a few examples of correctly capitalized CMOS book titles:
To learn more about Chicago referencing, check out our Chicago Author-Date Guide, and our Chicago Notes and Bibliography Guide.
Summary and Reference Guide
Although these may seem like a lot of capitalization rules, you’ll get the hang of them with a little practice. Below, we added a list of the major rules for APA, MLA, and CMOS for quick reference.
APA:
● Use sentence case.
● Capitalize the first word of the title.
● Capitalize the last word of the title.
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MLA:
● Use title case.
● Do capitalize the first and last word.
● Do capitalize all nouns, pronouns, verbs, adverbs, adjectives, and subordinating conjunctions.
● Do capitalize principal words that follow a hyphen.
● Do not capitalize articles, prepositions (regardless of length), coordinating conjunctions, and the word to in infinitives.
● Do not capitalize the second word after a hyphen in a compound modifier.
CMOS
● Use title case.
● Do capitalize the first and last word.
● Do capitalize all nouns, pronouns, verbs, adverbs, adjectives, and subordinating conjunctions.
● Do capitalize principal words that follow a hyphen.
● Do not capitalize articles, prepositions (regardless of length), coordinating conjunctions, and the word to in infinitives.
● Do not capitalize the second word after a hyphen in a compound modifier.
● Do not capitalize the conjunctions and, but, for, or, and nor, and the word as in any state.
● Do not capitalize a proper name that would be lowercase in text (e.g., Johann Wolfgang von Goethe).
● Do not capitalize the second part of a Latin species name.
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