Raja Yoga does not, after the unpardonable manner of some modern scientists, deny the existence of facts which are very difficult to explain; on the other hand, it gently, yet in no uncertain terms, tells the superstitious that miracles and answers to prayers, and powers of faith, though true as facts, are not rendered comprehensible through the superstitious explanation of attributing them to the agency of a being, or beings, above the clouds. It declares to mankind that each being is only a conduit for the infinite ocean of knowledge and power that lies behind.

       It teaches that desires and wants are in man, that the power of supply is also in man; and that wherever and whenever a desire, a want, a prayer, has been fulfilled, it was out of this infinite magazine that the supply came, and not from any supernatural being. The idea of supernatural beings may rouse to a certain extent the power of action in man, but it also brings spiritual decay. It brings dependence; it brings fear; it brings superstition. 

        It degenerates into a horrible belief in the natural weakness of man. There is no supernatural, says the Yogi, but there are in nature gross manifestations and subtle manifestations. The subtle are the causes, the gross the effects. The gross can be easily perceived by the senses; not so the subtle. The practice of Raja Yoga will lead to the acquisition of the more subtle   perceptions.

         All the orthodox systems of Indian philosophy have one goal in view, the liberation of the soul through perfection. The method is by Yoga. The word Yoga covers an immense ground, but both the Sankhya and the Vedantist schools point to Yoga in some form or other. The subject of the first lectures in the present book is that form of Yoga known as Raja Yoga. The aphorisms of Patanjali are the highest authority and text book on Raja Yoga.

        The other philosophers, though occasionally differing from Patanjali in some philosophical aspect, have, as a rule, acceded to his method of practice a decided consent. The first part of this book is comprised of several lectures to classes delivered by the present writer in New York. The second part is a rather free translation of the aphorisms (Sutras) of Patanjali, with a running commentary. Effort has been made to avoid technicalities as far as possible, and to keep the free and easy style of conversation.
          In the first part some simple and specific directions are given for the student who wants to practice, but all such are especially and earnestly reminded that, with few exceptions, Yoga can only be safely learned by direct contact with a teacher. If these conversations succeed in awakening a desire for further information on the subject, the teacher will not be wanting. The system of Patanjali is based upon the system of the Sankhyas, the points of difference being very few.

         The two most important differences are, first that Patanjali admits a Personal God in the form of a first teacher, while the only God the Sankhyas admit is a nearly perfected being, temporarily in charge of a cycle. Second, the Yogis hold the mind to be equally all-pervading with the soul, or Purusa, and the Sankhyas do not.