Since 2002, Dr. Matthew Clark has been giving talks on the history, background and philosophy of yoga; to date (2018) to twenty-five different yoga groups and organizations around the world. The aim of this book is to provide for the non-specialist a very short and concise introduction to the origins and practices of yoga. It is particularly aimed at students on yoga teaching training courses, providing a short, handy introduction to the essential topics of yoga philosophy. Nearly all of the information presented may be found in other publications; some that I have found most useful have been included in the Bibliography. Several friends and colleagues who are very knowledgeable in this field have kindly suggested some minor corrections, which have been incorporated in this edition, which is a revised version of the book that was first published in 2010. Dr. Matthew Clark, Hove (January, 2018) Post-Graduate Research Associate, School of Oriental and African Studies (SOAS), University of London.