The wizard known as Gandalf the Grey in J.R.R. Tolkien’s Middle-earth is Gandalf.
Gandalf is one of the Istari, a group of supernatural beings sent to Middle-earth in the Third Age to oppose Sauron. His grey clothing and name distinguish him from his later form, Gandalf the White. He is a guide and adviser to Bilbo, Frodo, and many other characters, although he often encourages others to make their own choices rather than solving every danger himself.
After confronting the Balrog on the Bridge of Khazad-dûm, Gandalf falls and later returns as Gandalf the White. This change reflects both his renewed authority and his altered role in the struggle against Sauron. Gandalf is sometimes mistaken for Saruman because both are Istari, but Saruman is the chief of the order and eventually betrays its purpose. Radagast is another member of the same order.