Regrettable indeed would it be if the mere fact that this little book bears a more or less technical title should tempt the careless to skip its pages or pitch it to that dreary limbo which attends even the best of text-books on subjects which we think do not concern us. The fruits of naval victory, the calamities attendant on naval defeat are matters which will come home--in Bacon's classic phrase--to the business and the bosoms of all of us, landsmen and seamen alike. Most Englishmen are at least dimly aware of this. They realise, more or less reluctantly perhaps, that a decisive British defeat at sea under modern conditions would involve unspeakable consequences, consequences not merely fatal to the structure of the Empire but destructive also of the roots of our national life and of the well-being of almost all individuals in these islands. Elementary prudence insists on adequate safeguards against evils so supreme, and amongst those safeguards the education of the people to-day occupies a foremost place. Our Empire's destinies for good and evil are now in the hands of the masses of the people. Sincerely as all lovers of ordered freedom may rejoice in this devolution of political power to the people, thoughtful men will be apt to reflect that an uninstructed crowd is seldom right in its collective action. If Ministerial responsibility has dwindled, _pro tanto_ that of each one of His Majesty's lieges has enormously increased; and it is more incumbent on the nation's rank and file to-day than ever in the past to equip themselves with the knowledge necessary to enable them to record their votes aright. It is from this point of view that this Manual should be read. It epitomises the principles upon which success in naval warfare depends. It shows how the moral factor in all cases and at every epoch dominates and controls the material; how the "_animus pugnandi_," as Mr Thursfield calls it, the desire to get at the enemy in "anything that floats," transcends every other weapon in a nation's armoury; how if that spirit is present, all other difficulties can be surmounted, and how without it the thickest armour, the biggest all-shattering guns shrivel in battle to the measure of mere useless scrap iron. This is the message of the book for the seaman. But--and this is of the essence of the whole matter--for the landsman it has also a lesson of a very different kind. His responsibility is for the material factor in naval war. Let him note the supreme value of the moral factor; let him encourage it with all possible honour and homage, but let him not limit his contribution to the nation's fighting capital to any mere empty lip-service of this kind. The moral factor is primarily the sailor's business. The landsman's duty is to see to it that when war comes our sailors are sent to sea, not in "anything that floats" but in the most modern and perfect types of warship that human ingenuity can design.