The principles of yoga apply alike to the highest. Spheres of contemplative and reli 'gions life and to the humblest objects of worldly pursuit. It is like the fundamental processes of algebra which enter into the solu tion of the highest problems of Differential Calculus no less than into the solution of ordinary questions of calculation. The com mentators of the Yoga Sh'astra however view it only in connection with the high meta physical and spiritual questions relating to humanity. This is no wonder, as the yoga Shastra itself deals with too many questions of this class. But the need of the modern day is to know the Yoga Shastra as a general and abstract system, irrespective of the objects to which it may be applied. In the following pages I have tried to present it in this shape. The appendix is intended by the publisher to explain how far the discoveries and the researches of modern Europe comport with the facts and theories of yoga.sh§stra.