'O Mysterio da Estrada de Cintra' is a collection of letters by Eça de Queirós and Ramalho Ortigão, first published in 1870. The narrative unfolds through a physician's account of a mysterious incident on the road to Cintra, involving masked assailants and a corpse. This work combines elements of mystery and social commentary, reflecting the complexities of human relationships and societal issues in 19th-century Portugal. It is notable for its early exploration of detective fiction within the Portuguese literary context.
