"As the zoologist bemoans the intrusion of alien species into the isolation of some island life, so the folk-lorist regrets that the isolation of the professional sailor has been invaded and well-nigh destroyed by the incredulous land-lubber." So the author begins, pointing to the necessity of carefully preserving authentic tales from those who lived on the seas. He notes that there are five basic classes of uncanny ship stories, "reward ships, punishment ships, specters, ships of the death voyage, and devil ships," providing an illustrative tale of each, followed by analysis of each theme, looking at similar stories from around the world.