Mary Florence Elinor Rainbow, known professionally as Mary Stewart, was born on 17 September 1916 in Sunderland, England. She embarked on her academic journey at Durham University, where she received an honorary D.Litt in 2009. Prior to dedicating herself to writing, Stewart served as a lecturer in English Language and Literature at the same university. In 1945, she married Sir Frederick Stewart, the former chairman of the Geology Department at Edinburgh University. Sir Frederick passed away in 2001.

Mary Stewart's literary career is highlighted by her authorship of twenty novels, a volume of poetry, and three books for young readers. Her work spans contemporary stories of romantic suspense as well as historical novels, earning her widespread admiration. Among her most notable contributions to literature is the Merlin Trilogy, an Arthurian saga composed of The Crystal Cave (1970), The Hollow Hills (1973), and The Last Enchantment (1979). The trilogy stands as her finest and most original achievement, with the first book being adapted into a children's television series in 1991. Stewart spent her later years residing in Scotland until her passing on 9 May 2014.