The Four Loves is the C.S. Lewis book that examines storge, friendship, eros, and agape.
Published in 1960, The Four Loves developed from a series of BBC radio talks. Lewis discusses four kinds of human affection using terms drawn from Greek vocabulary and Christian thought. Storge describes natural affection, especially the bond within families; philia describes friendship; eros describes romantic or sexual love; and agape describes self-giving love.
Lewis does not treat these categories as completely isolated. He considers how the loves overlap, how each can be distorted, and how dependence on human affection can become possessive or destructive. The book is therefore both a classification of relationships and a moral reflection on how people love one another.
The title can be confused with Lewis’s academic work The Allegory of Love, which studies medieval literature and was published in 1936. The Four Loves is a later, more accessible work aimed at general readers, while The Allegory of Love is a work of literary scholarship.