1 The rule in plain terms
The style rule for capitalizing titles of books, films, and songs is straightforward: capitalize the first and last words and all principal words. Principal words include nouns, pronouns, verbs, adjectives, adverbs, and subordinating conjunctions such as 'because,' 'although,' and 'if.' Lowercase articles ('a,' 'an,' 'the'), coordinating conjunctions ('and,' 'but,' 'or,' 'for,' 'nor,' 'so,' 'yet'), and prepositions of four or fewer letters ('at,' 'by,' 'for,' 'from,' 'in,' 'into,' 'of,' 'on,' 'onto,' 'to,' 'up,' 'with') unless they are the first or last word of the title. This rule applies uniformly to titles of books, films, and songs, whether they appear in running text, headlines, or captions.
For example, in the book title 'The Sound and the Fury,' 'The' is capitalized because it is the first word, 'and' is lowercase because it is a coordinating conjunction, and 'Fury' is capitalized because it is a noun. In the film title 'To Kill a Mockingbird,' 'To' is capitalized because it is the first word, 'a' is lowercase because it is an article, and 'Mockingbird' is capitalized because it is a noun. The same logic applies to song titles such as 'A Hard Day's Night,' where 'A' is capitalized as the first word, 'Hard' and 'Day's' and 'Night' are capitalized as principal words, and 'a' is lowercase in the middle. Always capitalize the first word after a colon or a dash, as in 'Star Wars: Episode IV—A New Hope.'
2 Why editors enforce it
Editors enforce consistent title capitalization because it is a hallmark of professional copy. When titles are capitalized haphazardly, readers may stumble or question the publication's attention to detail. A consistent approach also helps distinguish titles from surrounding text, especially in running prose where quotation marks or italics may not be enough. For instance, if a writer capitalizes every word in a title, the title can look like a headline or a proper noun phrase, which can confuse readers about what is actually a title and what is not.
Moreover, style guides exist to create uniformity across a publication. If one writer capitalizes 'The' in a title and another lowercases it, the inconsistency is visible and distracting. Editors enforce the rule to maintain a polished, trustworthy voice. It also aids in search and indexing, as consistent capitalization can affect how titles are parsed by databases and search engines. In short, the rule is not arbitrary; it is a practical tool for clarity and credibility. When readers see a title treated correctly, they can focus on the content rather than the formatting.
3 Where writers usually slip
Writers most often slip by capitalizing every word in a title, including short prepositions and articles. This mistake is common because many people are taught in school to capitalize all 'important' words, but they may not have a clear definition of what counts as important. Another frequent error is lowercasing a word that should be capitalized because it is a verb or a long preposition. For example, writers might lowercase 'Is' in 'What Is This Thing Called Love?' because they think 'is' is a minor word, but it is a verb and must be capitalized. Similarly, they might lowercase 'Between' in 'The Space Between Us' because they assume all prepositions are lowercase, but prepositions of five or more letters are capitalized.
A third slip is failing to capitalize the first word after a colon or dash. Writers might write 'Star Wars: a new hope' instead of 'Star Wars: A New Hope.' They may also forget to capitalize the last word of a title if it is a short preposition or article, as in 'Something to Believe In,' where 'In' must be capitalized because it is the last word. These errors often stem from haste or from applying inconsistent rules. On deadline, it helps to have a mental checklist: first and last words, principal words, and words after colons or dashes.
4 Applying the rule on deadline
When you are on deadline, the fastest way to apply the rule is to scan the title from left to right and identify the parts of speech. Start by capitalizing the first and last words, no matter what they are. Then, for each word in between, ask: is it a noun, pronoun, verb, adjective, adverb, or subordinating conjunction? If yes, capitalize it. If it is an article, a coordinating conjunction, or a preposition of four or fewer letters, lowercase it. If it is a preposition of five or more letters, capitalize it. Also, capitalize any word that follows a colon or a dash.
A practical trick is to remember the acronym 'CAPS': Capitalize All Principal words, but Short prepositions, articles, and coordinating conjunctions stay lowercase unless they are first or last. For example, in 'The Girl with the Dragon Tattoo,' 'with' is a preposition of four letters, so it is lowercase; 'the' is an article, so it is lowercase; but 'Girl' and 'Dragon' and 'Tattoo' are nouns, so they are capitalized. In 'A Song of Ice and Fire,' 'of' is lowercase, 'and' is lowercase, but 'Ice' and 'Fire' are capitalized. With practice, this becomes second nature, and you can apply it quickly even under pressure.
5 Legitimate exceptions
There are a few legitimate exceptions to the standard title capitalization rule. First, always capitalize a preposition of five or more letters, such as 'between,' 'through,' 'about,' 'above,' 'across,' 'after,' 'against,' 'along,' 'among,' 'around,' 'before,' 'behind,' 'below,' 'beneath,' 'beside,' 'beyond,' 'during,' 'except,' 'inside,' 'outside,' 'toward,' 'under,' 'until,' 'upon,' 'within,' and 'without.' This is because these words are long enough to be considered principal words by many style guides, including AP. Second, capitalize the first word after a colon or a dash, even if it would otherwise be lowercase. For example, 'The Lord of the Rings: The Fellowship of the Ring' capitalizes 'The' after the colon. Third, some titles are stylized in a way that intentionally breaks the rule, such as all-lowercase titles (e.g., 'beloved' by Toni Morrison is often styled as 'Beloved' in standard prose, but some authors prefer lowercase). In those cases, follow the author's or publisher's preferred styling if it is widely recognized, but for general copy, adhere to the standard rule. Finally, if a title is in a foreign language, apply the capitalization rules of that language if the title is well known in that form, but otherwise use English title case.
6 A worked example from the copy desk
Suppose a writer files a review of a new film and includes the sentence: 'The movie, “the curious case of benjamin button,” is based on a short story.' The copy editor sees several errors. First, the title should be capitalized according to the rule. The first word 'The' must be capitalized. 'Curious' is an adjective, so capitalize it. 'Case' is a noun, so capitalize it. 'Of' is a preposition of two letters, so lowercase it. 'Benjamin' is a proper noun, so capitalize it. 'Button' is a noun, so capitalize it. The last word 'Button' is already capitalized. So the correct title is 'The Curious Case of Benjamin Button.' The editor also notes that the title should be in quotation marks or italics, depending on the publication's style, and that the comma after the title should be inside the quotation marks if quotation marks are used. The corrected sentence reads: 'The movie, “The Curious Case of Benjamin Button,” is based on a short story.'
Another example: a writer writes, 'She sang “a hard day's night” at the talent show.' The editor corrects it to 'She sang “A Hard Day's Night” at the talent show.' Here, 'A' is capitalized as the first word, 'Hard' and 'Day's' and 'Night' are principal words, and 'a' is lowercase in the middle. The editor also ensures that the apostrophe in 'Day's' is correct and that the quotation marks are properly placed. These small corrections keep the copy clean and consistent, which is the goal of every copy desk.
7 Quick reference and related rules
For quick reference, remember these key points: capitalize the first and last words of a title; capitalize all nouns, pronouns, verbs, adjectives, adverbs, and subordinating conjunctions; lowercase articles, coordinating conjunctions, and prepositions of four or fewer letters unless they are first or last; capitalize prepositions of five or more letters; and capitalize the first word after a colon or dash. This rule applies to titles of books, films, and songs, as well as other creative works such as plays, television shows, and albums. Related rules include using italics for long works (books, films, albums) and quotation marks for short works (songs, poems, short stories) in many style guides, though AP style uses quotation marks for all titles of works. Always check your publication's style guide for specific preferences.
Another related rule is the capitalization of headlines, which often follow a similar but not identical set of guidelines. In AP style, headlines capitalize only the first word and proper nouns, which is different from title case. So do not confuse the two. Additionally, when a title contains a hyphenated word, capitalize both parts if they are principal words, as in 'The Self-Made Man.' But if the hyphenated word is a compound modifier and the second part is a short preposition or article, lowercase the second part, as in 'A Run-of-the-Mill Day.' Finally, when in doubt, consult a dictionary or the AP Stylebook. Consistency is more important than any single rule, so if your publication has a house style that differs, follow it.