Agatha Christie also wrote romance novels under the pseudonym Mary Westmacott, and was occasionally published under the name Agatha Christie Mallowan.Agatha Christie is the best-selling author of all time. She wrote 66 crime novels and story collections, fourteen plays, and six novels under a pseudonym in Romance. Her books have sold over a billion copies in the English language and a billion in translation. According to Index Translationum, she remains the most-translated individual author, having been translated into at least 103 languages.