Yoga sutras by Patanjali is a seminal work in yoga, this book is more about control of mind and the true goal of yoga. The sutras are extremely brief, and the translation in neat English makes it very easy for people to understand the ancient Sanskrit text. It starts with the birth and growth of spiritual man through the control of mind. In all, this is a "all in one" book for yoga philosophy written by the master himself. (Summary by sidhu177)