About the book: 1940 / Michelsen's book provides a detailed analysis of the submarine warfare conducted by Germany during the First World Imperialist War of 1914-1918. The author managed to concisely give a vivid and detailed description of all periods of underwater warfare. The fact that Michelsen himself was an active participant makes his work especially interesting. The translation has been slightly abridged and is an almost complete transcription of the original.