Which C.S. Lewis book develops the idea of four kinds of love?

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

The Four Loves was published in 1960 and grew from a series of BBC radio talks broadcast in 1958. Lewis examines four Greek terms as ways of discussing human affection: storge, philia, eros, and agape. He uses them as conceptual categories rather than as a claim that every relationship fits neatly into only one type.

Storge refers to natural affection, philia to friendship, eros to romantic or sexual love, and agape to charitable or self-giving love. Lewis argues that the forms can overlap and that natural loves become distorted when treated as ultimate or self-sufficient.

The book is sometimes confused with Mere Christianity because both explain Christian ideas to a broad audience. The Four Loves is more specifically organized around human relationships and the vocabulary of love. Its origin in radio broadcasts also connects it with Lewis’s wider work as a public religious communicator.