The Shadow Line, a short novel set at sea, is one of Joseph Conrad's later works, written from February to December 1915. The novella depicts the development of a young man upon taking a ship's captaincy in the Orient; the title's "shadow line" represents the threshold of the development.
The novella is notable for its dual-narrative structure. Its full title is The Shadow-Line: A Confession, which alerts the reader to the novella's retrospective nature. The ironic constructions following from the conflict between the "young" protagonist (who is never named) and the "old" drive much of the novella's underlying points: the nature of wisdom, experience, and maturity. Conrad also extensively uses irony by comparison, in the work, with characters such as Captain Giles and the ship's steward Ransome, used to emphasise strengths and weaknesses of the protagonist.
The novel has often been cited as a metaphor of the First World War, given its timing and references to a long struggle and the importance of camaraderie. This viewpoint may also be reinforced by the knowledge that Conrad's elder son, Borys, was wounded in the First World War.