Bhagavad Gītā has eighteen chapters, and each is designated as a type of yoga. The word yoga has many different meanings. In the Gītā it is used principally in the sense of the means undertaken to accomplish or to be united with one’s goal. Therefore, the word yoga can also be translated as “path,” as has been done here especially in the chapter titles. There are primarily three different types of yoga, namely, karma-yoga, jñāna-yoga, and bhakti-yoga. When we employ karma, or selfless action, for uniting with or reaching our goal, it is called karma-yoga. Similarly, when we cultivate jñāna, or the intuitive insight of our conscious identity with the Absolute, it is called jñāna-yoga. When bhakti, or devotion, is adopted as the means of attaining unity in love, it is called bhakti-yoga. In the case of the latter, bhakti is not only the means but also the goal.
There are two ways you can get understanding of the Tattva Sandarbha. One is that you can read the book and you will have intellectual understanding. Another way is that the book will reveal itself to you through direct experience. And then you will have direct understanding.
