What was C.S. Lewis’s full first name, beyond the initials “C.S.”?

C.S. Lewis’s full first name was Clive Staples. He was born Clive Staples Lewis in Belfast, Ireland, on 29 November 1898, and became widely known by his initials rather than by his given name.

Lewis disliked the name Clive as a child and reportedly chose the nickname “Jack,” a name he used for the rest of his life. “Jack” also became the familiar form used by friends, colleagues, and later readers. The initials C.S. therefore identify Clive Staples, not a longer formal name beginning with C.S.

Lewis’s middle name, Staples, came from his mother’s family. His brother Warren was known as Warnie, and the brothers remained close throughout their lives. Lewis later became a scholar of medieval and Renaissance literature, a Christian apologist, and the author of The Chronicles of Narnia. His professional reputation and literary fame made “C.S. Lewis” the permanent public name associated with his work.