The world of elite naval units - frogmen, commandos, midget submarines, demolition squads - and their operations are the subject of this history. It traces their development from the first such units in the 1890s to Italian/Austrian operations in World War I and the rise of the Italian MAS service between the wars. There is coverage of Japanese naval raids (including Pearl Harbor and Sydney), the Royal Navy X-Craft used in the Tirpitz attack, Mediterranean spying operations, German use of designs which failed to impede the Allies, Japanese suicide weapons and various unusual designs and operations, a planned Italian raid on New York, and the post-war rise of midget submarines and subsequent Soviet interest.