Our original intention, when we arranged for the publication of this book, and, in fact almost up until it went to press, was that it should be, in a measure, supplementary to our little book, The Science of Breath , by the same author-that is to say, it should take up the subject of "Hatha Yoga" with the exception of that phase of the subject (breathing, etc.) which has been covered in that book. But at the last moment we decided that it would be a mistake to publish a book on "Hatha Yoga" with such an important part of the subject as Yogi Breathing omitted, even though the subject had been covered in another book. to omit that important phase of the subject would be working an injustice to those who purchased the new book, as many of such purchasers would never have read the first book, and would be justified in expecting that the present book would treat of all phases of the general subject. So, we decided to incorporate those parts of Science of Breath which belonged strictly to the subject of "Hatha Yoga," omitting such portions a belonged rather to the other branch of the Yogi Philosophy, i.e., Raja Yoga.