As its title asserts, the book deals with science, not speculation. The monistic theory of the universe--the theory that matter, mind, consciousness, and life are all manifestations of one Substance--is now accepted by most thinkers; and if you accept this theory, you cannot deny the logical conclusions you will find herein. Best of all, the methods of thought and action prescribed have been tested by the author in his own case, and in the case of hundreds of others during twelve years of practice, with continuous and unfailing success. I can say of the Science of Being Well that it works; and that wherever its laws are complied with, it can no more fail to work than the science of geometry can fail to work. If the tissues of your body have not been so destroyed that continued life is impossible, you can get well; and if you will think and act in a Certain Way, you will get well. If the reader wishes to fully understand the monistic theory of the cosmos, he is recommended to read Hegel and Emerson; to read also "The Eternal News," a pamphlet by J. J. Brown, 300 Cathcart Road, Govanhill, Glasgow, Scotland. Some enlightenment may also be found in a series of articles by the author, which were published in _The Nautilus_, Holyoke, Mass., during the year 1909, under the title, "What Is Truth?" Those who wish more detailed information as to the performance of the voluntary functions--eating, drinking, breathing, and sleeping--may read "New Science of Living and Healing," "Letters to a Woman's Husband," and "The Constructive Use of Foods," booklets by W. D. Wattles, which may be obtained from the publishers of this book. I would also recommend the writings of Horace Fletcher, and of Edward Hooker Dewey. Read all these, if you like, as a sort of buttress to your faith; but let me warn you against making the mistake of studying many conflicting theories, and practicing, at the same time, parts of several different "systems"; for if you get well, it must be by giving your WHOLE MIND to the _right_ way of thinking and living. Remember that the SCIENCE OF BEING WELL claims to be a complete and sufficient guide in every particular. Concentrate upon the way of thinking and acting it prescribes, and follow it in every detail, and you will get well; or if you are already well, you will remain so. Trusting that you will go on until the priceless blessing of perfect health is yours, I remain, Very truly yours, WALLACE D. WATTLES. CHAPTER I. THE PRINCIPLE OF HEALTH. In the personal application of the Science of Being Well, as in that of the Science of Getting Rich, certain fundamental truths must be known in the beginning, and accepted without question. Some of these truths we state here:--