Since the middle of the twentieth century, analytic philosophers have taken diverse interests in love. Philosophers of mind have asked what kind of psychological state love is. A natural answer is that love is an emotion like any other. Some philosophers, however, find love to be an anomalous emotion, or even not to be an emotion at all. Most types of emotions seem to be triggered by, or partially to consist in, a belief that the emotion is warranted by some fact about its object. Fear of something, for example, typically involves the thought that the thing feared is dangerous or threatening. Love seems to be an exception, since it is unclear what fact about one's beloved might warrant one's love for this person. Some are willing to accept love as an emotion despite this anomaly, while others insist that love must be a psychological state...