Chronology of the War at Sea 1939–1945, Volume 1 by Jürgen Rohwer and Gerhard Hümmelchen is a detailed naval history reference covering the early years of the Second World War, with Volume 1 focusing on the period from 1939–1942. Presented in chronological order, the book records major naval engagements, convoy battles, submarine operations and fleet movements across the Atlantic, Pacific and other theatres of war. Designed as a factual day-by-day account rather than a narrative history, it provides a comprehensive overview of how the war at sea developed during the opening and middle years of the conflict.