Many persons sleep well only because they are still, like little children and animals, in the unreflective stage of life. That is the stage of the Natural Man, and it is good in itself; but later the mental life awakes, when consciousness of one’s self begins, and examination of one’s own desires develops. If not rightly understood or if not at least accepted, that development brings anxiety, unrest and disturbance of sleep, and breaks the harmony of the whole nature. The highest stage of development is the spiritual, the all-conscious state which includes and harmonizes the other two. In that we do not lose the ready, overflowing enjoyment of our bodily exercises and functions; rather they are intensified; the physical and the mental are united in the complete life. In order to attain this harmony we must examine the means that we and others use to gain rest and peace; some of these are instinctive and some prudential, and we must perceive why it is that these means work or fail to work in different cases. When, with all our getting, we have gotten this understanding, then, and not till then, all action becomes natural and joyful, for then we understand it all, and follow willingly the leading of the Spirit that is in Man. Care-charmer Sleep, son of the sable Night, Brother to Death, in silent darkness born. SAMUEL DANIEL. CHAPTER I SLEEP Sancho Panza says: “Now, blessings light on him who first invented sleep! Sleep which covers a man all over, thoughts and all, like a cloak; and is meat for the hungry, drink for the thirsty, heat for the cold, and cold for the hot. Sleep is the current coin that purchases all the pleasures of the world cheap, and the balance that sets the king and shepherd, the fool and the wise man, even.”—“Don Quixote.” Sleeping is the one thing that everyone practices almost daily all his life, and that, nevertheless, hardly anyone does as well as when he began. We have improved in our walking, talking, eating, seeing, and in other acts of skill and habit; but, in spite of our experience, few of us have improved in sleeping: the best sleepers only “sleep like a child.” It must be that we do not do it wisely, else we should by this time do it well. Even the race of mankind as a whole does not seem to be able to use sleep, to summon it, or to control it any better than primitive man did. We talk much of the need of sleep, and sagely discuss its benefits, but we know neither how to use the faculty of sleep to the best advantage nor how to cultivate it. Yet for ages men have studied the mystery of sleep. We have acquired many interesting facts concerning its variation, and have formulated a number of theories concerning its cause and advantages; nevertheless, science has given us little real knowledge of sleep, and less mastery over it.