Warning: Wikipedia contains spoilers
Set during the tenth (last) year of the Trojan War, the Iliad sings of how Achilles, the greatest Greek warrior, abandons the fight after king Agamemnon, the Greek commander in chief, takes an attractive captive Briseis who had been originally awarded to Achilles as a slave.
The death of Patroclus, Achilles' dearest friend, at the hands of the Trojan hero Hector, brings Achilles back for revenge, and he slays Hector. Later Hector's father, king Priam, comes to Achilles disguised as a beggar to ransom his son's body back, and Achilles is moved to pity; the funeral of Hector ends the poem.
The poem is a poignant depiction of the tragedy and poignancy of friendship and family destroyed by battle. The first word of the Greek is "Μηνιν" ("meinin", meaning "wrath"), because the main subject of the poem is the wrath of Achilles. Neither the beginning nor the end of the war is included in the Iliad.
Notable modern translations include Richmond Lattimore's, in verse that stays close to Homer's actual phrasing.