A Strange Manuscript Found in a Copper Cylinder is the most popular book by the Canadian writer James De Mille.

The satirical and fantastic romance is set in an imaginary semi-tropical land in Antarctica inhabited by prehistoric monsters and a cult of death-worshipers called the Kosekin.

[3] The main story of the novel is the narrative of the adventures of Adam More, a British sailor shipwrecked on a homeward voyage from Tasmania.

A secondary plot and framing device concerns four yachtsmen who find Adam More's manuscript sealed in a copper cylinder.

Contemporary reviews of the novel, unaware that it was written earlier, were coloured by the prior release of She and King Solomon's Mines by H. Rider Haggard.