This book is intended no less for those who do sleep well than for those who do not. It is just as important to be able to teach others to act well as to be able to do so ourselves. To teach we must analyze and comprehend our own action and its motives: for being able to do a thing well is far different from being able to teach it. In order to teach anything we must know how we do it and why others cannot do it. We never know anything thoroughly until we have tried to teach it to another.

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.