J.R.R. Tolkien’s first name at birth was John. His full birth name was John Ronald Reuel Tolkien, and the initials in his pen name represent John, Ronald, and Reuel.
Tolkien was generally known as Ronald during his personal and academic life, especially to family and friends. “J.R.R. Tolkien” became the form most familiar to readers, appearing on the title pages of his books and in scholarly references.
The name Reuel came from his father’s family tradition. Tolkien’s father was Arthur Reuel Tolkien, and Reuel was used as a family name rather than as a conventional first name. This can cause confusion because Ronald is often assumed to be Tolkien’s first name.
The initials are therefore not a shortened version of one compound name. They preserve three separate given names: John, Ronald, and Reuel. Tolkien’s use of initials also helped create the distinctive author identity associated with The Hobbit, The Lord of the Rings, and his wider legendarium.