The work opens by challenging the common assumption that romantic love has always existed as an immutable human sentiment. The author demonstrates that romantic love is actually a modern sentiment, less than a thousand years old, unknown to ancient civilisations like Greece and Rome, where women were kept in subjection and pre-matrimonial courtship did not exist. By examining cosmic attraction, chemical affinities, and vegetal fertilisation, the author clears away false biological analogies and arrives at the true laws of natural beauty, which rests on health and cross-fertilisation.
The text then systematically distinguishes romantic love from all other forms of affection, including impersonal love for nature, the love of animals, maternal and paternal love, filial and sibling love, and friendship. Maternal love is shown to be the most powerful of family affections, yet even it is surpassed in intensity and concentration by romantic love, which unites individuals utterly unrelated by blood.
Eleven distinct overtones of modern love are identified and analysed: individual preference, monopoly or exclusiveness, jealousy, coyness, gallantry, self-sacrifice, sympathy, pride of conquest, emotional hyperbole, mixed moods, and the admiration of personal beauty. Each of these components is traced through animal courtship, savage tribes, and historical epochs from Egypt, Judea, India, Greece, and Rome to the Middle Ages.
The historical survey reveals how the inferior position of women and the total absence of free courtship and individual choice stifled the romantic impulse in antiquity. The Greeks developed passionate friendships rather than romantic love, while the Middle Ages were marked by an ascetic hostility toward marriage and women, briefly interrupted by the poetic and militant chivalry of the troubadours and minnesingers.
Dante and Shakespeare are highlighted as the literary pioneers who first captured the true essence of modern romantic love. The final sections explore the modern period, contrasting the destructive effects of crude coyness with the refining influence of flirtation, and arguing that romantic love is the most powerful moral, aesthetic, and hygienic force controlling human life.
