Continuing his consideration of Christian morality, Lewis, with some apology and trepidation as he acknowledged that, at the time of writing this book, he was a single man, turns to Christian marriage. He delves deeply into the role of "being in love" and the beauty of the natural process (which is not reflected in novels and movies) of moving through the thrill of "falling in love" to the quieter, deeper, and more deliberate state of being in love. He closes with comments on the relationship between the husband and wife in decision-making.