Mary Stewart's writing career divides into two distinct parts. In her first period, according to Kay Mussell in the St. James Guide to Crime and Mystery Writers, Stewart "wrote a remarkable series of 10 popular novels of romantic suspense. . . . In her later phase, beginning in the late 1960s, Stewart's novels have been concerned with history and frequently with the occult. Her best-known work from this period is her four-volume series about King Arthur and Merlin." In the words of a National Observer critic, Stewart writes "like a magician, she conjures exotic moods and mysteries from mere words, her only aim to entertain."

Stewart explains in an article for Writer magazine: "I am first and foremost a teller of tales, but I am also a serious-minded woman who accepts the responsibilities of her job, and that job, if I am to be true to what is in me, is to...