There is no certainty about who wrote the Gita, or when; scholars have dated it anywhere between the third century BC and the sixth century of the modern era. At some point, it was incorporated into Hinduism’s mammoth epic, the Mahabharata, but it appears to have been written later than the rest of the larger work. In any case, the Gita is a self-contained, complete, and wholly satisfying reading experience in its own right, and is often published separately. Replete with quotable wisdom, its verses have traveled far and wide: Thoreau brought a copy with him to Walden Pond, and when physicist J. Robert Oppenheimer recalled observing the explosion of the first atomic bomb outside of Alamogordo, New Mexico, in 1945, he invoked Krishna’s description of himself as “the destroyer of worlds.” The poem possesses an epigrammatic eloquence that makes its guidance applicable cross-culturally: “Set thy heart upon thy work, but never on its reward,” is a key precept of its teaching, as is “ . . . do thy duty, even if it be humble, rather than another’s, even if it be great.”