How to Use Italics

Italics is a style of typeface in which the letters slant to the right: This sentence is printed in italics. (If you're writing something out in longhand, the equivalent of italics would be underlining.) Apart from the uses cited below for titles and naming conventions, italics are used to give emphasis to words and phrases in a sentence. For example, the question, "Are you going to wear that?" takes on an entirely different meaning if you italicize the last word: "Are you going to wear that?"

Using Italics With Style Guides

Although it's important to use italics appropriately in formal, academic writing, italic type is not always available in less formal communications, such as in emails and text messages. Journalism, medical writing, and a variety of other forms of professionally written materials rely on one of several style guides including Associated Press or AP Style, American Medical Association (AMA) Style, and the Chicago Manual of Style. In addition, many corporations, websites, and publishing companies have their own style guides that must be adhered to for written communications. The use of italics varies from style to style. (For example, in AP Style, titles are put inside quotation marks rather than being italicized.)

General Usage

For books and academic work, the following general rules apply, however, it's always a good idea to check if adherence to a particular style guide is required prior to embarking on any writing project.

Italicize the titles of complete works:

• Albums and CDs: 1989 by Taylor Swift
• Books: To Kill a Mockingbird by Harper Lee
• Magazines and journals (print and online): Sports Illustrated, Slate, and Journal of Linguistics
• Newspapers: The New York Times
• Movies: The Martian
• Plays: A Raisin in the Sun by Lorraine Hansberry
• Software programs: Microsoft PowerPoint 
• Television programs: Doctor Who
• Video games: Grand Theft Auto V
• Works of art: Nighthawks by Edward Hopper

The titles of comparatively short works—songs, poems, short stories, essays, and episodes of TV programs—should be enclosed in quotation marks.

As a general rule, italicize the names of aircraft, ships, and trains; foreign words used in an English sentence; and words and letters discussed as words and letters:

"These are the voyages of the starship Enterprise."
—Title sequence from the original Star Trek series

"From 1925 to 1953, a passenger train named the Orange Blossom Special brought vacationers to sunny Florida from New York."

"There is no danger that Titanic will sink. The boat is unsinkable and nothing but inconvenience will be suffered by the passengers."
—Phillip Franklin, Vice President of White Star Line

"Come kiss me, and say goodbye like a man. No, not good-bye, au revoir."
From "Chats With Jane Clermont" by William Graham

"Every word she writes is a lie, including and and the."
—Mary McCarthy on Lillian Hellman

As a general rule, use italics to emphasize words and phrases—but don't overwork this device:

"Then I started reading this timetable I had in my pocket. Just to stop lying. Once I get started, I can go on for hours if I feel like it. No kidding. Hours."
—From The Catcher in the Rye by J. D. Salinger,

Observations

"Italics rarely fail to insult the reader's intelligence. More often than not they tell us to emphasize a word or phrase that we would emphasize automatically in any natural reading of the sentence."
—From "The Philosophy of Punctuation." Opera, Sex, and Other Vital Matters by Paul Robinson, University of Chicago Press

"Think of italics as butterflies that might swoop across the page, allow them to flit about, land here and there, softly; gently; don't treat them as a blanket that must spread itself across the entire page. The butterfly approach will bring a dash of color; the blanket approach will darken everything."
—From Noble's Book of Writing Blunders (and How to Avoid Them) by William Noble, Writer's Digest Books

"Underlining is to... handwritten papers what italics are to more formal publishing... Today the only widespread use of underlined text is to denote clickable links in Web documents. (The newspaper convention, which I use as a newspaperman and which was also a response to a technical inability to use italics, is quotation marks for book, movie, and other titles.)"
—From The Elephants of Style by Bill Walsh, McGraw Hill