In this book, Lewis analyzes four manifestations of human love from a variety of perspectives: Affection, Friendship, Eros and Charity. Before dealing with them, he distinguishes -in the first chapter- two formal categories of human love: Love-that-gives or love of donation. Love-need, a self-interested love that arises from a lack or emptiness of the person himself. With this distinction he gives the key to the disorders of love: human loves "are really like God, but only by similarity, not by approximation". If these terms are confused, "we can give to our human loves the unconditional adhesion that we owe only to God. Then they become gods: then they become demons. Then they will destroy us. For natural loves that become gods do not remain loves. They continue to call themselves so, but in fact they may become complicated forms of hatred." This idea is applied by Lewis in the following chapters to the various loves: love for material things, affection, friendship, eros. After this journey, he turns to Charity. The author argues, in the light of the previous pages, that natural loves are not self-sufficient and require the Love of God. In this radical dependence of the four loves on Love, "here lies their true liberty. When God arrives (and only then), the demigods can stay".