Which 1937 novel by J.R.R. Tolkien introduces Bilbo Baggins?

The Hobbit is J.R.R. Tolkien's 1937 novel that introduces Bilbo Baggins. Bilbo begins the story as a comfort-loving hobbit in the Shire, but the wizard Gandalf and a company of dwarves draw him into a quest to reclaim treasure from the dragon Smaug.

Tolkien originally wrote the story for his children and developed it separately from the mythology that later appeared in The Silmarillion. The book was published by George Allen & Unwin on 21 September 1937 and became an immediate success. Its complete title is The Hobbit, or There and Back Again.

The Hobbit is often treated as a simple prequel to The Lord of the Rings, but its tone and intended audience are lighter. Tolkien revised parts of the text, especially material connected with Gollum and the Ring, so that it would fit the later story more closely. Bilbo's adventure therefore forms the narrative bridge between the two major works.