“In 1972, Avon Books published “The Flame and the Flower,” by Kathleen Woodiwiss — a hefty historical romance that traded chastity for steamy sex scenes. It arrived in the thick of the sexual revolution, and readers loved it: It was an instant bestseller that’s credited with birthing the modern romance genre.” https://www.washingtonpost.com/arts-entertainment/2021/04/15/romance-novels-history/