Cartland was one of the best selling and prolific romance authors of the 20th century. Her 723 novels were translated into 38 languages and she has the Guinness World Record for the most novels published in a single year (1976).

Cartland specialised in 19th-century Victorian-era pure romance. She also wrote books under her married name (Barbara McCorquodale) and briefly under the pseudonym of Marcus Belfry. She also wrote plays, music, verse, drama, magazine articles and operetta, and was a prominent philanthropist.