What was the title of C.S. Lewis’s 1942 book defending Christian belief during wartime?

C.S. Lewis’s 1942 book defending Christian belief during wartime was The Case for Christianity.

The book developed material from Lewis’s BBC broadcasts and presented arguments about Christian belief in a form intended for a broad audience. It discusses the human sense of right and wrong, the problem of moral law, and the Christian understanding of Jesus and redemption.

The Case for Christianity later formed the first part of Mere Christianity, the better-known book assembled from Lewis’s wartime broadcast talks. Because the titles are closely connected, readers sometimes treat them as interchangeable. They are related publications, but they are not the same title.

Lewis did not present the broadcasts as a denominational argument for one particular church. His aim was to explain what Christians shared across several traditions. That broad approach helped make the work influential beyond its original wartime radio audience.