The Bedford Glossary of Critical and Literary Terms - Ross Murfin 2018
Didactic: Instructive or providing information for a particular purpose. Literature is considered didactic when its primary aim is to teach readers some lesson — whether moral, political, religious, ethical, or practical. It might be argued that most literary works are didactic, insofar as they have some purpose or idea that the author seeks to convey. However, works that are essentially imaginative are usually not considered didactic.
EXAMPLES: Religious works such as the New Testament letters of Paul to early Christians and the Muslim holy book the Qur’an (Koran) are primarily didactic, as are the following works: the Kama Sutra (a fourth-century A.D. ancient Indian erotic manual), Geoffrey Chaucer’s “The Parson’s Tale” (c. 1387), Alexander Pope’s “An Essay on Criticism” (1711), and eighteenth-century English ladies’ conduct manuals. Many people would say that William Bennett’s anthology of moral tales entitled The Book of Virtues (1994) is a didactic work.