In Homer's The Odyssey, in the first four books, Telemachus is "encouraged" on his path to learn about his father's fate by Greek mythology's Athena, the goddess of...
...war, civilization, wisdom, strength, strategy, crafts, justice and skill.
Telemachus was in the Trojan War, being born after his father had already left for battle. Odysseus fought in the war, but the interference of the gods (particularly Poseidon) and some spectacular mythological creatures (Circe—the witch-goddess, Calypso—a sea nymph, Charybdis, the Lotus Eaters, the sirens, etc.) keep Odysseus from returning to the shores of Ithaca for ten additional years. (He is under Calypso's spell for seven of those years.) In Odysseus' absence, Telemachus and Penelope (the young man's mother and Odysseus' devoted wife) face would-be suitors wanting Odysseus' possessions as they try to win Penelope's hand in marriage. They assume that because so much time has passed since the war that Odysseus must be dead. Penelope wants nothing to do with any of them, but these men will not leave, making unethical demands of Penelope's hospitality because of Odysseus' absence.
In Book One, we learn that the Trojan War has lasted ten years, but Odysseus, a mighty warrior, offended Poseidon in his journey home by blinding his son, Polyphemus—a cyclops intent upon killing Odysseus (and his men). Odysseus is punished more because he bragged so much after defeating Polyphemus than for harming him—because his actions were very unsuitable for a great warrior. Odysseus has been kept now from returning home for ten years and Athena approaches Zeus to ask her father to free Odysseus to go home. Zeus' brother, Poseidon, is not present when Athena presents her case to her father, and Zeus allows her to arrange for Odysseus' homecoming. So Athena (in disguise) encourages Odysseus' son to go out to find his father.
In Book Two, Telemachus tries to find help in locating his father. The suitors refuse to aid Telemachus, so he departs secretly with the still-disguised Athena.
It is important to remember that Telemachus has never met his father and as he sets out not only to find his father, he also learns about him as well. In Book Three, he visits Nestor of Pylos, another solider in the Trojan War, who tells Odysseus' son great stories about his father's bravery. Nestor also sends his youngest son Pisistratus with Telemachus to Sparta, so he can visit another soldier who has also returned from the war—Menelaus.
In Book Four Telemachus meets Menelaus and his wife Helen. Menelaus shares his own story of the war and his return home; while "becalmed" off the shore of the island of Pharos, Proteus, the "Old Man of the Sea," (who lives there) told Menelaus of news that Odysseus was on Calypso's island.
In the meantime, Odysseus is freed from Calypso's power and starts his journey home.
By Book Fifteen, Telemachus heads for home, where the suitors plan to ambush him. In Book Sixteen, having evaded the suitors, Telemachus is reunited with his father, Odysseus, and they make plans to rid their home of the suitors. Athena also aids Odysseus in this endeavor.