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

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

Lewis was born in Belfast, Ireland, in 1898. “C.S.” came from his first and middle names, Clive Staples, rather than from a shortened pen name invented later. As an adult, he was widely known by his initials, especially in connection with his Christian apologetics, literary criticism, and fiction.

Lewis disliked being called “Jack,” but the nickname became the name used by friends and family. It originated in childhood after his dog Jacksie was killed by a car; he adopted “Jacksie” and later shortened it to “Jack.” This creates a common mix-up: Clive Staples Lewis and Jack refer to the same person, while C.S. Lewis is the public authorial name.