What links jkrowling enesbit cslewis and J.R.R Tolkien?

JK Rowling is the author of the very popular Harry Potterseries and E. Nesbit wrote many stories, including The Story of the Treasure Seekers and The House of Arden. C.S. Lewis (who was partially influenced by Nesbit) authored The Chronicles of Narnia series and J.R.R. Tolkien wrote The Lord of the Rings, one of the most influential works of epic fantasy in all time.

They are all authors of famous and influential works of fiction/fantasy in literature. They are all British. They all have written stories aimed at children and young people. They all are famous for having written books in a series. They all use initials instead of their real names. J.K. Rowling. E. Nesbit. C.S. Lewis. J.R.R. Tolkien.