 Many of the most iconic and memorable passages in literature achieve their currency through the use of illusion. Consider, for example, passages from the opening of two American novels published 100 years apart. Herman Melville's Moby Dick, published in 1851, opens with perhaps the most recognizable sentence in all of American literature. Call me Ishmael. Ralph Ellison's Invisible Man, published in 1950, also partakes of illusion when its narrator and main character introduces himself. I am an invisible man, not like those who haunted Edgar Allan Poe, nor am I one of your Hollywood movie Ectoplasms. The use of illusion by these authors exemplifies both what an illusion is and why it is used. Illusions are generally regarded as brief but purposeful references within a literary text to a person, place, event, or to another work of literature. Illusion is distinguished from other forms of reference, the many ways that works of literature can call out to other works of art by its brevity and often by its indirection, though just how indirect an illusion is can vary by a wide degree. An illusion is not a deep meditation but a passing signal that can sometimes escape notice if you're not reading carefully. However, illusions are an essential tool for literary artists that often serve to situate their own works within the wider culture and the contexts of literary history. So, how does this work? What do illusions achieve and why do authors use them? Let's refer back to our examples. When the narrator of Moby Dick introduces himself to the reader, he refers to himself as Ishmael as a way to make himself more anonymous, and indeed the reader would not necessarily need to pause and ask the question, what is the significance of the narrator naming himself Ishmael? However, a careful reader would indeed be rewarded by her curiosity. Ishmael is a biblical name from the book of Genesis. He's the oldest son of Abraham and brother of the more well known Isaac. Ishmael is known for being an outcast from a great family. According to an angel who protects Ishmael's mother Hagar, he is to be a wild man whose, quote, hands will be against every man and every man's hand against him. This allusion to the biblical Ishmael achieves two goals then. Without having to do much work at all, we're only three words into the novel itself, we already learn a lot about Ishmael, that he is at odds with the world and with those around him. To keep from, quote, methodically knocking people's hats off, he seeks the solitude that only an ocean voyage can provide. But the illusion also accomplishes a broader goal. It establishes the solemn but ambitious tone that this novel conjures. While Ishmael shoves off with Captain Ahab on the Pequod from the shores of Nantucket, this is also the world of Noah and his Ark, of Jonah and the Whale. And biblical reference serves to expand the novel's presence beyond the 19th century, onto a plane with the most consequential and ancient human stories. In Ralph Ellison's Invisible Man, illusion is used again, this time more directly, but just as quickly, as an act of self-definition by the novel's narrator. Though invisible, he is not some specter from Edgar Allan Poe, he says. Though he's defining himself in the negative by describing who he is by what he is not, his associations are telling. They predict the assumptions and associations of his readers, who likely know of Poe's work, thus creating an immediate relationship based on shared knowledge and reference. This narrator might not want to be associated with such dark figures, as Poe's Roderick Usher or William Wilson, but his protests only go so far. It's difficult not to associate him with these characters from the American Gothic tradition, when we find him hunkered down in a basement, yearly lit by hundreds of light bulbs, where he lives, quote, not only visible, but formless. So while this reference to Poe in the opening lines of Invisible Man is lightning quick, the illusion performs a lot of heavy lifting. To a student of literature then, the research sometimes required to fully understand illusions, especially when they're identified in older texts, is like exploring the subtle but potentially dense backdrops of an intricate painting, without which the foregrounded material would not be as rich and impactful. Illusions draw connections between text and reader by harnessing them into the space where context resides. Illusions are the tendrils of a text that expand its field of association, but that also serve to intensify the intellectual and aesthetic possibilities of a given moment.