What was the full birth name of the author known as C.S. Lewis?

The full birth name of the author known as C.S. Lewis was Clive Staples Lewis.

Lewis was born in Belfast, Ireland, on 29 November 1898. His initials came from his first and middle names, although he was usually called “Jack” by family and friends. The nickname arose from a childhood incident involving a dog named Jacksie.

Lewis’s older brother, Warren, was known as Warnie, and the brothers remained close throughout their lives. They later shared interests in literature, history, and mythology, interests that strongly influenced Lewis’s fiction and scholarship.

Readers sometimes assume that “C.S.” was a pen name or an abbreviation of a longer literary name. It was simply Lewis’s initials. He used them professionally for books ranging from medieval literary criticism to Christian apologetics and children’s fantasy. His name is also sometimes confused with Clive Hamilton, the pseudonym he used for an earlier work of poetry.