As a literary device, it is most common in dramatic genres (plays, animated cartoons, film) but can also be found in prose fiction. The term can also be applied to poems, which usually take the form of the thoughts or speech of a single individual. In everyday usage, a long, rather boring speech by a conversation partner is sometimes called a monologue as well.
The term 'dramatic monologue' is used both for monologues in plays and for a poetic genre.
Playwrights such as Shakespeare and Goethe used the soliloquy to great effect in order to reveal their characters' personal thoughts, emotions, and motives without resorting to third-person narration. Hamlet's "To be or not to be" speech may well be the most famous soliloquy. There is a dramatic convention that soliloquies, like "asides" to the audience, cannot necessarily be heard or noticed by the other characters, even if they are clearly delivered within earshot.
Monologues can also be distinguished with regard to their frame of reference. A speech addressed to a character or a group of characters within the play (including the speaker himself) is called an interior monologue. A speech addressed to the audience is called an exterior monologue. Sometimes a speech addressed to an absent character is also called an exterior monologue. The 'interior monologue' in drama must not be confused with the narrative device of the same name which often occurs in modernist prose fiction
The speaker generally talks about a subject, but inadvertently reveals something about his character. The dramatic monologue combines the dramatic impact of the stage monologue with the potential of more elaborate and suggestive use of language; on the printed page, where the words can be re-read and pondered, there is the potential to evoke more complex layers of intent and meaning.
Twentieth-century dramatic monologues include T. S. Eliot's The Love Song of J. Alfred Prufrock, Hugh MacDiarmid's A Drunk Man Looks at the Thistle, Ted Hughes' Hawk Roosting, and John Ashbery's Daffy Duck in Hollywood.
The term "monologue" is also applied to a form of popular narrative verse, sometimes comic, often dramatic or sentimental, that was performed in music halls or in domestic entertainments in the late nineteenth and early twentieth century. Famous examples include Idylls of the King, The Green Eye of the Yellow God and Christmas Day in the Workhouse.
Outstanding examples in twentieth-century fiction include James Joyce’s Ulysses, Virginia Woolf’s Mrs. Dalloway, William Faulkner's As I Lay Dying, J.D Salinger's The Catcher in the Rye and several novellas by Arthur Schnitzler.
Famous comic monologists include Lenny Bruce, Mort Sahl, Chris Rock, Dave Chappelle, George Carlin, Jack Parr, Billy Connolly, Bill Cosby, Lord Buckley, Johnny Carson, David Letterman, Jay Leno, Rove McManus, Bob Hope, Stanley Holloway, Julius Tannen, George Robert Sims, Ellen DeGeneres, John Leguizamo, Jerry Seinfeld, Don Rickles, Jimmy Kimmel, Dane Cook,George Lopez and Conan O'Brien. Some of the aforementioned performers often perform what is referred to as a solo show, and some practitioners of the form wrestle with stories and themes which mix the comic and the dramatic, namely Spalding Gray, Garrison Keillor, and Eric Bogosian.
Along with comic books, James Bond films feature some of the earliest monologue/deathtrap combinations. For example, From Russia With Love's assassin, Donald "Red" Grant, can barely resist the temptation to gloat over James Bond's impending demise, allowing himself to reveal the true architect of the plot (SPECTRE) and the finer points of how MI6 will be scandalized with circumstantial evidence surrounding Bond's (faked) murder/suicide. The practice reached its most absurd level in the Batman live action show of the late sixties. In almost every episode, Batman and Robin would be defeated and captured, the villain would reveal a ludicrously elaborate deathtrap, then finally the villain would monologue about how the heroes would die and what their plan was. These shows/movies were later lampooned in the Austin Powers movies, and on Venture Bros. The Last Action Hero and other shows by which time all seriousness is removed and the monologue/deathtrap becomes a joke. The term "monologuing" was (at least in part) popularized by the movie The Incredibles, in which the character Frozone tells Mr. Incredible about an encounter the former had with the villain Baron von Ruthless ("the guy has me on a platter and he won't shut up") and later when Syndrome admits that Mr. Incredible "caught me monologuing" upon attacking him during their first encounter on the villain's island.
Some rants are used not to attack something, but to defend an individual, idea or organization. Rants of this type generally occur after the subject has been attacked by another individual or group.
Rants are used often in situations requiring monologue. Comedians, such as Lewis Black, Adam Carolla, and Rick Mercer, use rants as a way to get their message or punch-line across to the listening audience.
In Watt's book "Swoosh" (1908), while planning a raid, a single member of a band of pirates uses emotive language, revealing himself to be of higher intelligence than the Cap'n. The angry Cap'n questions his manliness with a monologue with insults and illogic, known as The Cap'n's Rant:
"Do we have a sashaying pirate on board, a fanciful folly of a fiend? Do ye keelhaul scurvy dogs or do ye serenade them from the crow’s nest? Do ye shake ye cutlass and howl at the moon or do ye shake ye head and faint oh so sweetly at the sight of unkempt hairy men?"