Although the genre is very old, the romance novel or romantic novel discussed in this article is the mass-market version. Novels of this type of genre fiction place their primary focus on the relationship and romantic love between two people, and must have an "emotionally satisfying and optimistic ending." There are many subgenres of the romance novel, including fantasy, historical romance, paranormal fiction, and science fiction.
A thriving genre of works conventionally referred to as "romance novels" existed in ancient Greece. Other precursors can be found in the literary fiction of the 18th and 19th centuries, including Samuel Richardson's sentimental novel Pamela, or Virtue Rewarded (1740) and the novels of Jane Austen. Austen inspired Georgette Heyer, the British author of historical romance set around the time Austen lived, as well as detective fiction. Heyer's first romance novel, The Black Moth (1921), was set in 1751.
The British company Mills and Boon began releasing escapist fiction for women in the 1930s. Their books were sold in North America by Harlequin Enterprises Ltd, which began direct marketing to readers and allowing mass-market merchandisers to carry the books.
According to the Romance Writers of America, the main plot of a mass-market romance novel must revolve about the two people as they develop romantic love for each other and work to build a relationship. Both the conflict and the climax of the novel should be directly related to that core theme of developing a romantic relationship, although the novel can also contain subplots that do not specifically relate to the main characters' romantic love. Furthermore, a romance novel must have an "emotionally satisfying and optimistic ending." Others, including Leslie Gelbman, a president of Berkley Books, define the genre more simply, stating only that a romance must make the "romantic relationship between the hero and the heroine ... the core of the book." In general, romance novels reward characters who are good people and penalize those who are evil, and a couple who fights for and believes in their relationship will likely be rewarded with unconditional love. Bestselling author Nora Roberts sums up the genre, saying: "The books are about the celebration of falling in love and emotion and commitment, and all of those things we really want." Women's fiction (including "chick lit") is not directly a subcategory of the romance novel genre, because in women's fiction the heroine's relationship with her family or friends may be as important as her relationship with the hero.
Some romance novel authors and readers believe the genre has additional restrictions, from plot considerations (such as the protagonists' meeting early on in the story), to avoiding themes (such as adultery). Other disagreements have centered on the firm requirement for a happy ending; some readers admit stories without a happy ending, if the focus of the story is on the romantic love between the two main characters (e.g., Romeo and Juliet). While the majority of romance novels meet the stricter criteria, there are also many books widely considered to be romance novels that deviate from these rules. Therefore, the general definition, as embraced by the RWA and publishers, includes only the focus on a developing romantic relationship and an optimistic ending. Escapism is important; an Avon executive observed that "The phone never rings, the baby never cries and the rent's never overdue in romances".