In Book III, Telemachus is talking to Nestor, who was with Odysseus and the rest at the Trojan War. He hopes he can get information about his father. Sadly for him, Nestor does not really know anything about where Odysseus is. All he can really tell Telemachus is who he should ask next.
Nestor knows that many ships on their way back from Troy were blown around by strong winds and ended up in strange places. He thinks that it is possible that Odysseus might have been on one of these. He thinks that Menelaus, king of Sparta, might know more. Menelaus has been voyaging around and might have heard more about where Odysseus is.