Who is John Galt?

John Galt is a man who loves his life. He is a creator, not a looter. He is a producer not a moocher. He is a man of reason, not a mystic. He's a man who relies on productive effort, not political pull. He's everything our leaders in politics, business, science and art should be, but largely aren't. He's a hero.

Francisco to Dagny in Atlas Shrugged, Part Two, Chapter V:

John Galt is Prometheus who changed his mind. After centuries of being torn by vultures in payment for having brought to men the fire of the gods, he broke his chains and he withdrew his fire—until the day when men withdraw their vultures.

John Galt is science wrapped in philosophy. (Remember his major subjects?) He is capability plus insight as to ends. He is self-sufficiency, self-aware. He is the man of Kipling's IF, and his is the world, and everything that's in it. He is man, qua man.