The Iliad is one of the most widely-studied books in the world, and several categories of knowledge can be gained from it. First and most obviously, one learns about the story of the Trojan war, one of the foundational narratives of Western literature. Although only a fairly small section of the story is told in the Iliad itself, there are many references to the parts of the tale that occur outside the poem, and the reader gains an appreciation for the personalities and roles of some of the major characters involved, particularly Achilles, Agamemnon, Odysseus, Hector, and Andromache.
The Iliad also teaches the reader a great deal about Greek culture in more general terms. The tenets of the Homeric code, the system of honorable conduct for aristocratic and royal warriors, is much emphasized, as is the social and political structure of Mycenaean Greece. The role of the gods is particularly interesting to students of religion and anthropology. The gods in the Iliad are portrayed as immensely powerful and brilliant, but they are still subject to fate as well as to human emotions and caprices. People from monotheistic cultures, in which a single god is thought to be omniscient and omnipotent, can learn much about polytheism and its believers from the Iliad.