This is the authoritative text book of Yoga, one of the six systems of Indian philosophy. Sanskrit Text and translation with commentary which provides a full picture of what Yoga is, what its aims are, how it can be practised, and what liberation of the soul means.
Look here -- we shall die! Bear this in mind always, and then the spirit within will wake up. Then meanness will vanish from you, practicality in work will come, you will get new vigor in mind and body, and those who come in contact with you will also feel that they have really got something uplifting from you.
-Swami Vivekananda