Bilbo Baggins is the protagonist of The Hobbit and also makes a few appearances in The Lord of the Rings, two of the most well-known of J. R. R. Tolkien's fantasy writings. The story of The Hobbit featuring Bilbo is also retold from a different perspective in the Chapter The Quest of Erebor in Unfinished Tales.
In Tolkien's narrative conceit, in which all the writings of Middle-earth are 'really' translations from the fictitious volume of The Red Book of Westmarch, Bilbo is the author of The Hobbit and translator of The Silmarillion.