Within the past decade there has been a general popular awakening from the former uninterested attitude toward these phenomena of the physical and mental processes by which we keep in touch with the things outside ourselves. A fair knowledge of the rudiments of biology, of physiology, and of psychology now has become part of the curriculum of our schools and colleges. And of these three sciences it is psychology which has entered so deeply into our everyday life—business life as well as personal—that at last no one can escape its influence. And no one wishes to, for psychology in a sense has become the intellectual handmaiden of all who think in terms of to-day, with to-day’s amazing development of insight into the mortal meanings of our very selves, body always as well as soul. Our scientific realization of our true continuity with all things else goes on apace, and our personal relations to the boundless, perhaps Infinite, Cosmos of consciousness, life, and energy seem ever clearer. Thus, in a way, the sense organs give us personal anchorage in a Sea which else sometimes, from its very immensity and stress, would overwhelm us. Our range, although the broadest as yet vouchsafed to life, is as it were but a mere line out into the complexity of the Actual. The first step to the appreciation of this complexity and its implications for the human mind is knowledge of the conditions of its acquirement,—of the sense organs and of the perplexing brain behind them. Editorial duty or privilege fails to know much as yet of the detailed contents of these several volumes. But the editor does know not a little about the arrangers and expounders of the volumes’ contents, and he knows that they are women and men of conspicuous sense—trustworthy in every sense. The books are the best of their kind and are in a class by themselves. They are the standard authority for ordinary use. These volumes when disposed as a red-backed set on one’s library shelf will be a set of books to be proud of. And the high school boys and girls and their fathers evenings and on Sundays and their mothers at the club all alike will think of them as highly valued friends, both wise and agreeable, as pleasant to meet for an hour as the most welcome visitor well could be. No higher “authority” exists than that which these authors represent; and it would be hard to find those who could set forth “authority” more gracefully. Each knows that literary _enjoyment_ usually goes hand in hand with that _wisdom_ which extended is the director of Life itself.