C.S. Lewis examines four kinds of love in The Four Loves. The 1960 book discusses affection, friendship, erotic love, and charity, using both philosophical reflection and Christian theology.
The English terms in the book are often paired with Greek words: storge for natural affection, philia for friendship, eros for romantic or sexual love, and agape for self-giving divine love. Lewis does not present these categories as completely isolated emotions; real relationships may contain more than one kind.
The book developed from a series of BBC radio talks broadcast in 1958. Lewis revised and expanded the material for publication, making the book more than a simple transcript of the broadcasts.
A common mistake is to count only three forms because Lewis gives special attention to affection, friendship, and eros before discussing charity as the highest or divine form. Charity is still one of the four loves examined in the work, so the title’s number is literal.