Ruth Downie is a British author of historical mystery novels, best known for the Medicus series set in the Roman Empire during the early second century. After studying English at university, she worked as a librarian before becoming a full-time writer. Her first novel, published in Britain as Ruso and the Disappearing Dancing Girls and in the United States as Medicus, introduced Gaius Petreius Ruso, an overworked and financially troubled Roman army doctor stationed in Britannia.
The series follows Ruso and Tilla, a British woman from the northern tribes who becomes his partner, as they investigate murders, disappearances and political intrigues across Roman Britain, Gaul and Rome. Downie combines carefully researched details of military medicine, provincial government and everyday Roman life with understated humour and character-driven mysteries. The sequence comprises eight full-length novels, from Medicus to Memento Mori, together with the novella Prima Facie.