Eugène Léon Canseliet (December 18, 1899, Sarcelles – April 12, 1982, Savignies), was a French writer and alchemist. He was the first and one of the few students of the mysterious alchemist known as Fulcanelli, and may have been Fulcanelli himself. He wrote the preface for each of his alleged master's books (Le mystère des cathédrales and Les demeures philosophales).