Which C.S. Lewis book was published in 1940 as his first major work of Christian apologetics?

The Problem of Pain was published in 1940 as C.S. Lewis’s first major work of Christian apologetics.

The book examines why suffering exists if God is both good and powerful. Lewis discusses divine omnipotence, human freedom, punishment, animal pain, and the Christian understanding of heaven. It is an argumentative work rather than a personal memoir.

Lewis wrote it before the death of his wife, Joy Davidman, and before the grief described in A Grief Observed. That distinction matters because readers sometimes connect all of Lewis’s writing about suffering with his later bereavement.

Mere Christianity developed from wartime radio talks and appeared in book form in 1952. The Problem of Pain is earlier and has a more systematic, philosophical structure.