Gandalf is the wizard who recruits Bilbo Baggins in J.R.R. Tolkien's The Hobbit.
At the beginning of the novel, Gandalf visits Bag End and helps arrange Bilbo's involvement in Thorin Oakenshield's expedition to reclaim the Lonely Mountain from Smaug. Bilbo initially resists the adventure, but eventually joins the dwarves as their burglar.
Gandalf is one of the Istari, supernatural beings sent to Middle-earth to oppose Sauron. In The Hobbit he is usually called Gandalf the Grey. In The Lord of the Rings, he returns as Gandalf the White after confronting the Balrog beneath Khazad-dûm.
Tolkien gave the character names from several linguistic and literary sources, including Old Norse material. Gandalf is distinct from Saruman, who is also an Istar but becomes an ally of Sauron. Radagast is another member of the same order.