What were C.S. Lewis’s initials short for?

C.S. Lewis’s initials stood for Clive Staples.

Lewis was born Clive Staples Lewis in Belfast in 1898. The name “Clive” was rarely used in his adult life because, as a child, he adopted the nickname “Jacksie,” later shortened to “Jack.” Friends and family continued to call him Jack, while his publications usually appeared under the initials C.S. Lewis.

The initials became one of the most recognizable author signatures of the twentieth century. They appear on his fiction, Christian apologetics, literary criticism, and works for children. Readers sometimes assume the C stands for “Charles,” but that is not his recorded name.

His middle name, Staples, came from his mother’s family. The combination of a formal birth name, a private nickname, and a public set of initials reflects the different identities Lewis used in family life, academic circles, and publishing.