J.R.R. Tolkien’s middle name was Reuel, and his full name was John Ronald Reuel Tolkien.
Tolkien was baptized John Ronald Reuel Tolkien in 1892. The name Reuel came from a family tradition: Tolkien’s father, Arthur Reuel Tolkien, also had Reuel as a middle name. Tolkien gave the same middle name to his son Christopher Reuel Tolkien, who became an important editor and scholar of his father’s unpublished writings.
The initials J.R.R. therefore stand for John Ronald Reuel. Ronald was the name Tolkien generally used in ordinary life, while John was his first given name. Reuel is sometimes mistaken for one of Tolkien’s invented names because it resembles names found in his legendarium, but it was a real family name.
Christopher Tolkien’s editorial work after his father’s death helped publish The Silmarillion, Unfinished Tales, and many volumes of Middle-earth drafts and commentary.