For any science to be useful, it must address two aspects—theory and practice. Even the best of theoretical knowledge is insufficient in itself to solve the problems of life. And if knowledge is not put into practice, it only serves the purpose of intellectual entertainment. The Bhagavad Gita is not content with providing a lofty philosophical understanding; it also describes clear-cut techniques for implementing its spiritual precepts for everyday life. These techniques of applying the science of spirituality in our lives are termed “Yog.” Hence, the Bhagavad Gita is also called “Yog Śhāstra,” meaning, the scripture that teaches the practice of Yog.
Inexperienced spiritual practitioners often separate spirituality from temporal life; some look on beatitude as something to be attained in the hereafter. But the Bhagavad Gita makes no such distinction, and aims at the consecration of every aspect of human life in this world itself. Thus, all its eighteen chapters are designated as different types of Yog because they deal with methodologies for the application of spiritual knowledge to practical life. These chapters also describe various systems of Yog, such as karm-yog, jñāna-yog, and bhakti-yog.