The agreements concluded in 1904 and 1907 by Britain, France, Russia and Japan are defined in this study as a Quadruple Entente, a more complete description than the commonly used Triple Entente (which omits Japan) and an acknowledgement that Japan had become a nation of considerable significance to Europe. This wider perspective on the crucial prewar years shows how, in its political context as well as its geographical terrain and its general impact, the First World War was a world war in every sense.