Book excerpt: The Yoga Sutra is the living source wisdom of the yoga tradition. Using it as a guide, we can unlock the hidden power of yoga, and experience the promise of yoga in our life. The Yoga Sutra is as fresh today as it was 2200 years ago when it was discovered by the sage Patanjali. It is the first practitioner-oriented commentary which is fully grounded in a living tradition. By applying its living wisdom in our practice, we can achieve the purpose of life: lasting fulfillment and ultimate freedom.