The first initial in J.R.R. Tolkien’s name represents John. His full name was John Ronald Reuel Tolkien, although he was commonly known by his initials or as Ronald among family and friends.
Tolkien was baptised John Ronald Reuel Tolkien. Ronald was the name he generally used in everyday life, while Reuel was a family name. The arrangement of the initials can therefore obscure the fact that his first given name was John.
The initials became closely associated with his published identity after The Hobbit and The Lord of the Rings made him internationally famous. His name is sometimes written with periods as J.R.R. Tolkien, while some style systems omit them.