race and nation as a distinct entity, while endeavouring to show throughout the whole narrative the part which each fills in the general drama of human effort, conflict, and progress. A universal history may, however, while conforming to this established method, follow it out along a special line, which shall give prominence to some one leading idea or principle. Such a line or point of view has been found for the present work in the relation of man to his physical environment--that is to say, to the geographical conditions which have always surrounded him, and always must surround him, conditions whose power and influence he has felt ever since he appeared upon the globe. This point of view is more comprehensive than any one of those above enumerated. Physical environment has told upon each and every one of the lines of human activity already enumerated that could be taken to form a central line for the writing of a history of mankind. It has influenced not only political institutions and economic phenomena, but also religion, and social institutions, and art, and inventions. No department of man’s life has been independent of it, for it works upon man not only materially but also intellectually and morally. [Illustration: UNEARTHING THE RUINS OF ANCIENT BABYLON IN THE TWENTIETH CENTURY This photograph illustrates how present-day exploration brings the remains of the ancient wonder cities of Babylonia to light after the sleep of ages. Much valuable knowledge of Babylon has been acquired quite recently as a result of excavations now being carried on under the supervision of English, American, French, and German explorers. ] As this is the idea which has governed the preparation of the present book, as it is constructed upon a geographical rather than a purely chronological plan (though, of course, each particular country and nation needs to be treated chronologically), some few pages may properly be devoted here to a consideration of the way in which geography determines history, or, in other words, to an examination of the relations of Nature, inorganic and organic, to the life of man. MAN’S PLACE IN NATURE’S KINGDOM Though we are accustomed to contrast man with Nature, and to look upon the world outside ourselves as an object to be studied by man, the conscious and intelligent subject, it is evident, and has been always recognised even by those thinkers who have most exalted the place man holds in the Cosmos, that man is also to be studied as a part of the physical universe. He belongs to the realm of Nature in respect of his bodily constitution, which links him with other animals, and in certain respects with all the phenomena that lie within the sphere of biology.