We hear often that love is patient and kind, not envious or prideful. We hear that human love is a reflection of divine love. We hear that God is love. But how do we understand its work in our lives, its perils and rewards? Here, the incomparable C. S. Lewis examines human love in four forms: affection, the most basic, general, and emotive; friendship, the most rare, least jealous, and, in bein...