Did You Know? The oldest example of intertextuality is New Testament that quotes or cites from the Old Testament.

The word is said to be derived from the Latin word intertexto, which means to intermingle while weaving. According to the Merriam-Webster dictionary, intertextuality means the complex interrelationship between a text and other texts taken as basic to the creation or interpretation of the text. According to A Glossary of Literary Terms by M. H. Abrams, intertextuality is used to signify the multiple ways in which any one literary text is made up of other texts, by means of its open or covert citations and allusions, its repetitions and transformations of the formal and substantive features of earlier texts, or simply its unavoidable participation in the common stock of linguistic and literary conventions and procedures that are "always already" in place and constitute the discourses into which we are born. . . . any text is in fact an "intertext"-the site of an intersection of numberless other texts, and existing only through its relations to other texts.

The term was first coined by the Bulgarian-French philosopher and literary critic, Julia Kristeva in 1966. The term was built based on the semiotic studies (done by Swiss linguist and semiotician Ferdinand de Saussure) of how signs derive within a text and dialogism (studies done by Russian philosopher and literary critic Mikhail Bakhtin) which is the study of multiple meanings of each text. It also supports French literary theorist and philosopher Roland Barthes's theory that the creator and the creation are unrelated. The meaning of the creation or text readers and their relation to the network of texts was brought up in the reading process. According to Kristeva, when readers read a new text, they are always influenced by other texts, which they have read earlier. When a writer borrows from other texts while writing his own, he attaches layers of meanings to his work as well. When that work is read under the light of the others, it gives it a new meaning and interpretation. According to Kristeva, any text is constructed as a mosaic of quotations; any text is the absorption and transformation of another. Graham Allen explains the concept like this―Intertextuality seems such a useful term because it foregrounds notions of relationality, interconnectedness and interdependence in modern cultural life. In the Postmodern epoch, theorists often claim, it is not possible any longer to speak of originality or the uniqueness of the artistic object, be it a painting or novel, since every artistic object is so clearly assembled from bits and pieces of already existent art.

In a broader sense, there are two types of intertextuality: vertical and horizontal. Australian scholar John Fiske made this distinction. Horizontal intertextuality means the same level references, i.e., books referring to other books. On the other hand, vertical intertextuality means a book referring to films, songs, etc. It can happen vice versa as well. Apart from these two, the literary devices such as allusion, quotation, calque, plagiarism, translation, pastiche, parody, etc., are different types of intertextuality.

► For Whom the Bell Tolls by Ernest Hemingway Hemingway has based the title of his novel published in 1940 on John Donne's poem XVII Meditation. An excerpt of the poem is usually published under the name "No Man is an Island." The title of the novel has been taken from "And therefore never send to know for whom the bell tolls; It tolls for thee." Hemingway also incorporates Donne's philosophy into his story with the Spanish civil war as a backdrop. The intertextuality between the two literary pieces has expanded the theme of the novel. ► Lord of the Flies by William Golding Golding draws the adventure theme of young boys on a lonely island from R. L. Stevenson's Treasure Island. However, he changed Stevenson's exalted tales of the adventures into the tales of how savagery can take over innocence, cause loss of civilization, and depict gruesome reality. ► The Great Gatsby by F. Scott Fitzgerald Fitzgerald alludes to T. S. Eliot's poem The Waste Land, which was published two years before the novel. Like Eliot's poem, The Great Gatsby presents a barren land, the valley of ashes, where nothing grows. In both the literary works, the land is called spiritually dead. In Fitzgerald's land of ashes, there is only weather-beaten advertisement, and in Eliot's waste land, there is a heap of broken images. Fitzgerald's novel also refers to the Greek myth of King Midas. ► Wide Sargasso Sea by Jean Rhys Rhys take the character, Mr. Rochester's wife, from Emily Bronte's Jane Eyre and creates an alternative story for it. She changes the setting of her novel and provides a backstory for her characters to write the story from Mrs. Rochester's point of view. She also address issues like racism, role of a woman, and colonization. ► Daddy by Sylvia Plath As the narrator of the poem speaks about her father, she describes him to have a 'Mein Kampf' look. It refers to the Nazi leader Adolf Hitler's autobiography with the same name. This allusion makes the character of the narrator's father more striking. ► The 1995 American comedy Clueless is loosely based on Jane Austen's Emma. The connection can be seen in the Harry Potter series as well as Lord of the Rings. In both the cases, the protagonist is an orphan, both have dark lords, and both have wise old wizards who help the protagonists. Likewise, a popular animated TV series The Simpsons is known to adopt several characters and scenes from different movies.