Who was C.S. Lewis’s demanding private tutor known as “the Great Knock”?

C.S. Lewis’s demanding private tutor known as “the Great Knock” was William T. Kirkpatrick.

Kirkpatrick tutored Lewis from 1914 to 1917 at Great Bookham in Surrey. He was a former headmaster with a reputation for rigorous logic and relentless questioning. Under Kirkpatrick’s instruction, Lewis studied languages, literature, history, and philosophy in an intensive environment that helped prepare him for university-level academic work.

Lewis later portrayed aspects of this period in Surprised by Joy, describing his tutor’s powerful intellect and conversational method. Kirkpatrick’s nickname, “the Great Knock,” referred to the force of his critical examination rather than to a literary or military title. He is sometimes confused with Lewis’s brother Warren or with later Oxford friends, but Kirkpatrick was the educator responsible for this formative stage of Lewis’s schooling.