Which C.S. Lewis book was adapted from his 1958 radio talks about love?

The C.S. Lewis book adapted from his 1958 radio talks about love was The Four Loves.

The Four Loves developed from a series of radio talks Lewis gave for the BBC in 1958. The book examines four Greek terms used to distinguish kinds of affection: storge for natural or familial affection, philia for friendship, eros for romantic love, and agape for self-giving love.

Lewis does not treat these categories as isolated boxes. He considers how the forms of love overlap, how affection can become possessive, and why human love can be understood in relation to divine love. His examples draw on literature, ordinary relationships, and Christian theology.

The work is sometimes confused with The Allegory of Love, Lewis’s much earlier scholarly study of medieval literature. The titles sound related, but they serve different purposes: The Four Loves is a popular theological and philosophical discussion, while The Allegory of Love is an academic literary history published in 1936. The book version of The Four Loves appeared in 1960.