The Lumos Duo spellbook is a book containing information on, and instructions of how to perform, Lumos Duo. It was owned by Professor Charity Burbage, who kept it in a room of the Muggle Studies Classroom in Hogwarts Castle for unknown reasons. Ronald Weasley later came across it during the 1993–1994 school year, and used it to learn the spell, which proved invaluable against the Hinkypunks which Professor Burbage had kept in glass cases.