What does he learn from his visit with the dead: his mother, Agamemnon, Achilles, Elpenor, Tiresias?

The essay prompt is: Odysseus travels to the underworld. What is his reason for going? Does he accomplish his goal? Why or why not? What does he learn from his visit with the dead: his mother, Agamemnon, Achilles, Elpenor, Tiresias?