If I were asked what, in my opinion, distinguishes the thought of the present day from that of a previous generation, I should feel inclined to say, it is the fact that people are beginning to realize that Thought is a power in itself, one of the great forces of the Universe, and ultimately the greatest of forces, directing all the others. This idea seems to be, as the French say, "in the air," and this very well expresses the state of the case--the idea is rapidly spreading through many countries and through all classes, but it is still very much "in the air." It is to a great extent as yet only in a gaseous condition, vague and nebulous, and so not leading to the practical results, both individual and collective, which might be expected of it, if it were consolidated into a more workable form. We are like some amateurs who want to paint finished pictures before they have studied the elements of Art, and when they see an artist do without difficulty what they vainly attempt, they look upon him as a being specially favoured by Providence, instead of putting it down to their own want of knowledge. The idea is true. Thought _is_ the great power of the Universe. But to make it practically available we must know something of the principles by which it works--that it is not a mere vaporous indefinable influence floating around and subject to no known laws, but that on the contrary, it follows laws as uncompromising as those of mathematics, while at the same time allowing unlimited freedom to the individual. Now the purpose of the following pages, is to suggest to the reader the lines on which to find his way out of this nebulous sort of thought into something more solid and reliable. I do not profess, like a certain Negro preacher, to "unscrew the inscrutable," for we can never reach a point where we shall not find the inscrutable still ahead of us; but if I can indicate the use of a screw-driver instead of a hatchet, and that the screws should be turned from left to right, instead of from right to left, it may enable us to unscrew some things which would otherwise remain screwed down tight. We are all beginners, and indeed the hopefulness of life is in realizing that there are such vistas of unending possibilities before us, that however far we may advance, we shall always be on the threshold of something greater. We must be like Peter Pan, the boy who never grew up--heaven defend me from ever feeling quite grown up, for then I should come to a standstill; so the reader must take what I have to say simply as the talk of one boy to another in the Great School, and not expect too much.