Allusion is a technique used in literature in which a literary work references another work of literature, work of art, historical figure, place, or event. In general, this passing reference is not explained by the writer, so only readers who are familiar with the referenced work tend to notice it. Writers use allusion in literature for a variety of different reasons. In some cases, a literary reference is used simply because it already communicated what the writer wants to say better than he could have himself. In most cases, though, writers make allusions because of the many emotions or ideas that readers may associate with the works to which the writer alludes.
Biblical allusions are among the most common types of allusion in literature. Biblical allusions are so prevalent because the Bible is widely read, so more people are likely to notice and recognize Biblical references. Additionally, many people, particularly those with religious backgrounds, make strong emotional and intellectual associations with certain passages of the Bible. The use of the Biblical allusions serve not only to communicate lines from the Bible, but also to evoke the many emotions and ideas that people associate with those passages. Allusion, then, goes far beyond the literal words on the page and taps into a body of thought and emotion that people associate with other subject matters.
In many cases, allusions serve a more specific purpose than simply tapping into a body of associations. In some cases, a reference to another work is given in a context that is drastically opposed to the original meaning. This technique is often used to refute the meaning of the original and to assert a new meaning. Other uses of allusion in literature actually reference several different sources simultaneously in order to create new associations and to force the reader to evaluate one or more works in the context of others.
Some works of literature are densely pack with allusions, many of which refer to specific and obscure works that the general reader could have little hope of understanding. To the highly educated reader, however, this can lead to a complex reading experience packed with emotionally and intellectually charged associations. An individual who does not understand most of the references, on the other hand, might find the reading to be completely incomprehensible. Some writers use allusion in literature in this way in order to create a complex and association-filled reading experience. Others do so in order to make a reading experience filled with challenges and puzzles that can only be solved with a great deal of research and study.