

In his remaining four chapters, Lewis treats love under four categories ("the highest does not stand without the lowest"), based in part on the four Greek words for love: affection, friendship, eros, and charity. Throughout the rest of the book, Lewis goes on to counterpoint that three-fold, qualitative distinction against the four broad types of loves indicated in his title. Appreciative love", to go along with Need-love and Gift-love. From the latter, he developed what he called "a third element in love. Lewis continues his examination by exploring the nature of pleasure, distinguishing Need-pleasures (such as water for the thirsty) from Pleasures of Appreciation, such as the love of nature.

However, he swiftly happened on the insight that the natures of even these basic categorizations of love are more complicated than they at first seemed: a child's need for parental comfort is a necessity, not a selfish indulgence, while conversely parental Gift-love in excessive form can be a perversion of its own. John's words "God is Love", Lewis initially thought to contrast "Need-love" (such as the love of a child for its mother) and "Gift-love" (epitomized by God's love for humanity), to the disparagement of the former. at the time for their frankness about sex. The book was based on a set of radio talks from 1958 which had been criticised in the U.S.

Lewis which explores the nature of love from a Christian and philosophical perspective through thought experiments.
