Synopsis The subject of 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 to the free and easy style of conversation. In the first part some simple and specific directions are given for the student who wants to practise, 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.