The Bhagavad-gita is the compact essence of all spiritual philosophy; at the onset of a world war, the warrior Arjuna asks his friend Krishna about the purpose of life, the difference between the self and the material body, and how to understand the ultimate cause of all causes. In just over seven hundred verses, Krishna comprehensively answers all of Arjuna's questions and then reveals His identity as the Supreme Personality of Godhead Himself, appearing on earth to usher in a new era of spiritual understanding.