What is C.S. Lewis’s first given name?

C.S. Lewis’s first given name was Clive.

His full name was Clive Staples Lewis. He was commonly known by the initials C.S. Lewis, especially after becoming a published author. The initials helped create a formal authorial identity while remaining faithful to his legal name.

As a child, Lewis adopted the nickname Jack, and friends and family generally continued to call him Jack throughout his life. The nickname came from an early personal association with a childhood dog named Jacksie. This means that Clive and Jack refer to the same person, although Clive is his first given name.

Lewis used the name C.S. Lewis on works ranging from literary criticism to Christian apologetics and fiction. His brother Warren also wrote under the name W.H. Lewis. Readers sometimes expand the initials incorrectly or assume that “C.S.” stands for a different first name, but the standard full form is Clive Staples Lewis.