Robert Eustace was the pen name of Eustace Robert Barton (1854–1943), an English doctor and author of mystery and crime fiction with a theme of scientific innovation. He also wrote as Eustace Robert Rawlings. Eustace often collaborated with other writers, producing a number of works with the author L. T. Meade and others. He is credited as co-author with Dorothy L. Sayers of the novel The Documents in the Case, for which he supplied the main plot idea and supporting medical and scientific details.
L. T. Meade was the pseudonym of Elizabeth Thomasina Meade Smith (1844–1914), a prolific writer of girls' stories. She was born in Bandon, County Cork, Ireland, daughter of Rev. R. T. Meade, of Nohoval, County Cork. She later moved to London, where she married Alfred Toulmin Smith in September 1879.