This book covers the excitement and dangers that accompany submarine warfare. It is a personal memoir by a submarine captain. Prior to World War I, prevailing naval opinion considered the submarine an ineffective weapon for blockading an enemy country. Submarines, filled with exposed piping and crammed with machinery, had no space to take prisoners aboard. Additionally, the submarine could never carry enough sailors to provide crews to man captured ships. Therefore, the submarine was considered a useless weapon against civilian shipping. A German U-boat prowls an angry sea, ca. 1916 In February 1915 the German government announced its solution to the problem -- unrestricted submarine warfare. The Germans realized they didn't have to capture a merchant ship, just sink it - crew and all. They declared a war zone around the British Isles within which they would sink any allied merchant vessel on sight. Fifty ships were hit between February and September including the liner Lusitania. One hundred thirty-eight Americans were among the 1,198 lives lost in the Lusitania sinking. American public opinion was outraged, many clamoring for war. President Wilson protested to the Germans. Afraid that America might join the war, and mindful that they didn't have enough subs to do the job right, the Germans suspended their campaign -- but only temporarily.