Derived from ancient Indian philosophy, yoga synthesizes physical movement and spiritual meditation, all intended to help us serve God, our own spirit, and each other. The Bhagavad Gita, often called the first book of yoga, describes the four branches of yoga: bhakti yoga, the path of devotion or divine love; karma yoga, the yoga of action and duty; jnana yoga, the yoga of intellect and self-realization; and raja or ashtanga yoga, which strives toward mental control through meditation and movement.