J.R.R. Tolkien's novel featuring Bilbo Baggins as its main protagonist is The Hobbit. Published in 1937, it begins with Bilbo living a quiet life in Bag End before Gandalf and a company of Dwarves recruit him for a journey to the Lonely Mountain.
Bilbo's adventure includes the encounter with Gollum beneath the Misty Mountains, where he finds the One Ring, and the confrontation with Smaug. His gradual change from a comfort-loving Hobbit into a resourceful and courageous companion forms the book's central character arc.
The Hobbit is set before The Lord of the Rings and introduces locations, peoples, and objects later developed in greater depth. Its tone is generally lighter and more direct, reflecting Tolkien's original conception of the story as a children's book.
The title is sometimes confused with The Lord of the Rings because both prominently feature Bilbo and the Ring. Bilbo is the principal protagonist of The Hobbit, while Frodo carries the central quest in most of The Lord of the Rings.