A number of major blockades, including the Continental System in the Napoleonic Wars, the War of 1812, the American Civil War, and World Wars I and II, in addition to the increased use of peacetime blockades and sanctions with the hope of avoiding war, are examined in this book. The impact of new technology and organizational changes on the nature of blockades and their effectiveness as military measures are discussed. Legal, economic, and political questions are explored to understand the various constraints upon belligerent behavior. The analysis draw upon the extensive amount of quantitative material available from military publications.