The Four Loves summarizes four kinds of human love: affection, friendship, erotic love, and the love of God. Masterful without being magisterial, this book offers wise, gentle, candid reflections on the virtues and dangers of love, drawing on sources from Jane Austen to St. Augustine.

The chapter on charity (love of God) may be the best thing Lewis ever wrote about Christianity. Consider his reflection on Augustine's teaching that one must love only God, because only God is eternal, and all earthly love will someday pass away. He questions, "Who could conceivably begin to love God on such a prudential ground—because the security (so to speak) is better?"

His description of Christianity here is no less forceful and opinionated than in Mere Christianity or The Problem of Pain, but it is far less anxious about its reader's response—and therefore more persuasive than any of his apologetics. When he begins to describe the nature of faith, Lewis writes: "Take it as one man's reverie, almost one man's myth. If anything in it is useful to you, use it; if anything is not, never give it a second thought."