A Strange Manuscript Found in a Copper Cylinder is an 1888 novel by the Canadian writer James De Mille. It was serialized posthumously and anonymously in Harper's Weekly, and published in book form by Harper and Brothers of New York City in 1888. It was serialized subsequently in the United Kingdom and Australia, and published in book form in the United Kingdom and Canada. Later editions were published from the plates of Harper & Brothers' first edition during the late 19th and early 20th centuries.