What was C.S. Lewis’s 1955 book about the four kinds of love?

The Four Loves was C.S. Lewis’s 1955 book about four kinds of love. It developed ideas first presented in a BBC radio broadcast series and examines affection, friendship, erotic love and charitable love.

Lewis uses Greek terms to distinguish the forms: storge for natural affection, philia for friendship, eros for romantic or sexual love, and agape for selfless or divine love. The English text does not treat these categories as sealed compartments; Lewis explores how they overlap and how each can become distorted.

The book belongs to Lewis’s Christian apologetic writing, but it also draws on classical language, personal observation and literary examples. It is often confused with The Allegory of Love, Lewis’s earlier scholarly study of medieval literature, or with The Four Loves television and radio adaptations.