The human population is the base of human existence. This, when considered, seems an inescapable proposition. But in the minds of most men it must have an absurd remoteness. The process of population has seemed like primordial creation itself, hardly a thing to be touched by mere scruple. Beyond the scope of any deliberation, the peopling of the earth has, for mankind as a whole, remained unquestioned as the earth, an axiom behind which there was no going and from which all proceeded. But according to a relentless gathering of awareness, as witnessed in an abundance of recent writings, it appears that history has marched to a new point. The condition of the world is being modified by a constellation of emergencies, and any observation and reflection on them, any rough glance at the outlines of trends in the life of the world, points to the swelling flood of population as the central reality in every perspective on the future.