Headlines and Titles of Works
A. Chicago lowercases all prepositions in titles, including words that aren’t always prepositions. For example, we’d write The World according to Garp. Most so-called participial prepositions (verb forms that can also function as prepositions)—according (to), assuming, barring, concerning, considering, during, notwithstanding, owing (to), provided, regarding, respecting, and speaking (of), among others—rarely appear in titles of works. And the ones that occur most often (like “according to,” “considering,” and “during”) normally function as prepositions, which makes the job of an editor following Chicago style a little easier. (A title like “Teachers According More Time to Students,” in which “According” functions as a verb and is therefore capitalized, would be hard to find.) Note that other styles capitalize prepositions based on length alone. AP and APA, for example, capitalize words of more than three letters, including prepositions; Chicago and MLA lowercase all prepositions regardless of length.