What do the initials “C.S.” stand for in the name C.S. Lewis?

The initials “C.S.” in C.S. Lewis stand for Clive Staples. Lewis was born Clive Staples Lewis in Belfast, Ireland, on 29 November 1898.

He was usually called “Jack” by family and friends rather than Clive. The nickname developed from his childhood use of the name Jacksie, which he adopted after the death of a childhood dog. “C.S. Lewis” became his established author name.

Lewis’s middle name, Staples, came from his mother’s family. His full name is sometimes incorrectly expanded as Charles or Christopher Staples Lewis, but contemporary biographical records give Clive Staples Lewis. His brother was Warren Hamilton Lewis, commonly known as Warnie.

Lewis published fiction, literary criticism, Christian apologetics, and medieval studies under his own initials. Those initials became especially recognizable through works such as The Chronicles of Narnia, The Screwtape Letters, and Mere Christianity.