Which C.S. Lewis book explores four kinds of human love?

The C.S. Lewis book that explores four kinds of human love is The Four Loves.

The Four Loves was published in 1960 and develops ideas Lewis first presented in a BBC radio series. The book discusses four Greek terms used to describe kinds of love: affection, friendship, erotic love, and charitable love. Lewis uses the terms storge, philia, eros, and agape to distinguish these forms.

The work is a Christian reflection, but it also draws on philosophy, literature, and ordinary human relationships. Lewis emphasizes that the forms of love can overlap and that natural loves may become destructive when treated as ultimate or self-sufficient.

The title is sometimes shortened incorrectly to “Four Loves.” The canonical title includes the definite article “The.” It is also distinct from Lewis’s other nonfiction works, including The Problem of Pain, which addresses suffering and Christian belief rather than a classification of love.