I DESIRE simply to say that I commenced taking an active interest in submarines in 1904. I wrote my first book on the subject, _Submarines of the World's Navies_, in 1910, and I have watched and written of the rise of these and kindred weapons for the past fifteen years of rapid development in peace and war, finally taking a humble part in the defeat of the great German submarine armada during the years 1914-1918. C. D.-F. 1919. INTRODUCTION WHILE Great Britain remains an island, with dominion over palm and pine, it is to the sea that her four hundred millions of people must look for the key to all that has been achieved in the past and all that the future promises in the quickening dawn of a new era. Not only over Great Britain alone, however, does the ocean cast its spell, for it is the free highway of the world, sailed by the ships of all nations, without other hindrances than those of stormy nature, and navigated without restriction from pole to pole by the seamen of all races. It was the international meeting-place, where ensigns were "dipped" in friendly greeting, and since the dawn of history there has been a freemasonry of the sea which knew no distinction of nation or creed. When the call of humanity boomed across the dark, storm-tossed waters the answer came readily from beneath whatever flag the sound was heard. But in August, 1914, there came a change, so dramatic, so sudden, that maritime nations were stunned. Germany, in an excess of war fever, broke the sea laws, and laughed while women and children drowned. Crime followed crime, and the great voice of the Republican West protested in unison with that of the Imperial East. Still the Black Eagle laughed as it flew far and wide, carrying death to whomsoever came within its shadow, regardless of race and sex. But there was an avenger upon the seas, one who had been rocked in its cradle from time immemorial, and to whom the world appealed to save the lives of their seamen. It sailed beneath the White Ensign and the Blue, and with aid from France, Italy and Japan it fought by day and by night, in winter gale and snow, and in summer heat and fog, in torrid zone and regions of perpetual ice to free the seas of the traitorous monster who had, in the twentieth century, hoisted the black flag of piracy and murder. For three years this ceaseless war was waged, and then, with her wonderful patience exhausted, the great sister nation of the mother tongue joined her fleets and armies with those of the battle-worn Allies and peace came to a long-suffering world.