Italics are used for long works, car names, and movie and television program titles. Quotation marks are used to denote portions of a text, such as chapter titles, magazine articles, poetry, and short tales. Both methods can be used for the same work.
In general, unless you are using both methods for emphasis, only use one or the other. It is acceptable to use both methods in the same work, but only use one method for each title. This is called "emphatic styling." For example, if the author wanted to emphasize that his poem was meant to be read aloud, he could write: "To A Mouse: A Lullaby".
Using italics instead of quotation marks for titles means that the title will not be reproduced in any form of media, including websites, blogs, social networking posts, etc. This is because these formats do not support italicized text. Only bolded or underlined text is supported in these cases.
Titles written in all caps are also considered emphatic styles. However, like with italicizing a poem's title, titles written in all caps cannot be displayed in some media forms. Only the cap-first style is supported in these instances.
If the source is self-contained and independent, italicize the title. Italicized book, play, film, magazines, databases, and online titles are italicized. If the source is part of a larger work, put the title in quotation marks. Articles, articles, chapters, poems, websites, songs, and speeches are all surrounded by quote marks. Film and television episodes are separated from the rest of the show's credits by using the word TV.
In general, use lowercase for titles. However, if the title itself contains dashes or other punctuation, capitalize it. For example: "The Dangers of Drinking Alcohol," "Why Does My Phone Not Show Up In The Wireless Network?"
Italicize the titles of longer publications, such as books, magazines, databases, and websites. Titles published in longer works, such as articles, essays, chapters, poetry, Web pages, songs, and speeches, should be surrounded by quote marks. The words "a title" should be italicized, not punctuated with a period.
Long titles, such as novels, movies, or record albums, should be italicized in general. For the names of shorter pieces of work, such as poems, essays, book chapters, songs, TV programs, and so on, use quote marks. Long words or phrases that need to be emphasized within the title should be set off using boldface type.
Poems, essays, book chapters, music, and television shows should all have their titles in quote marks.
Full-text titles, such as books or newspapers, should be italicized. Short work titles, such as poems, essays, short tales, or chapters, should be surrounded by quotation marks. If the name of the book series is italicized, titles of books that are part of a larger body of work may be put in quotation marks. For example: "The Iliad" and "The Odyssey".
Italics are generally used to signify titles and names of certain works or items, allowing that title or name to stand out from the surrounding language. Italics can be employed for emphasis in writing, but only on rare occasions. The convention of using italics to represent words or phrases not found in regular typefaces is called "literary styling".
The most common reason for using italics is to distinguish a work or item that is considered important or significant enough to warrant such treatment. For example, a book written in an author's own hand-painted italic script is known as a "hand-lettered" book. A poem printed in italics is a "poetic" print.
Other reasons for writing in italics include distinguishing words or phrases that should be emphasized (such as key words in a document), indicating a foreign word or phrase, or duplicating the font size of another word or phrase within the text. Writing in italics is also used by authors as a way of providing commentary on the text, or as a form of indirection. An author may wish to emphasize a particular word or phrase by writing it in boldface instead; however, this practice is more commonly used in journalism.
In general usage, the term "italic" applies to both the font style and the manner of punctuation used with it.