Overview
In Lord of the Rings, the inhabitants of Middle Earth join to save themselves from enslavement by the malevolent Sauron. Centuries before, Sauron forged a Ring, putting much of his power into it, to control through a series of lesser rings, men, dwarves, and elves. Some men fell into his power, but an alliance of men and elves defeated him, and the Ring was cut from his hand. It should have been destroyed, but a human prince, Isildur, took it. Isildur was slain, and the Ring fell into a river. There, the hobbit-like Deagol eventually found it. His friend Sméagol killed Deagol for the Ring. From Sméagol it passed to Bilbo Baggins, who, innocent of its powers and dangers, takes it back to his home and eventually leaves it to his cousin and heir Frodo Baggins. Once it is understood what the Ring is, and that Sauron is trying to recover it, it becomes clear that it must be destroyed. It can, however, only be destroyed in the same fire in which it was forged, the volcano Orodruin deep in Sauron's realm. It appears a rash and hopeless mission, requiring that the last forces of Middle Earth fight and act as a decoy while sending Sauron's ultimate weapon back into the heart of his realm. The very unlikelihood of the mission confuses Sauron. The Ring is destroyed in an act of providential irony, but not without enormous loss and a fundamental change to Middle Earth.

The Hobbit
The Lord of the Rings is preceded by a prologue, The Hobbit, which introduces the Hobbits, Middle Earth, and Sauron's Ring. Bilbo Baggins, on a superficially unrelated adventure finds, steals, or wins—actually a little of all three—a magic ring. His first act while wearing the ring is to spare the life of its previous owner, Gollum, despite the creature's murderous intentions. Bilbo uses the ring throughout the rest of the book to help his companions, raising their estimation of him from something like an awkward piece of baggage to a statesman, if not quite a hero. Returning home, he finds that his reputation will never recover from his adventure and that he does not care.

The Fellowship of the Ring: Book 1
Gandalf the Wizard, an old family friend of Bilbo and his companion in The Hobbit, suspects Bilbo's ring is Sauron's lost Ring. Bilbo's advanced age and vigor are unusual even for a hobbit, and the Ring has begun to fill him with unease. Bilbo leaves the Shire, bequeathing the Ring, on Gandalf s advice, along with the rest of his estate to his cousin and heir Frodo. Eventually, Gandalf returns and makes a final test that convinces himself and Frodo that the Ring is Sauron's. Sauron has built up his power and is searching for his Ring. He sends his most terrible servants, the Ringwraiths, to find it. Frodo, his servant Sam, and cousins Merry and Pippin barely manage to elude them with the help of Aragorn, the heir of the ancient kings who had fought Sauron in the past. Frodo nearly falls under Sauron's power when he puts on the Ring and is wounded by a Ringwraith.