Zoroastrianism is the religion of ancient Iran, dating back centuries before the coming of Islam. It stresses the duality between goodness and evil, light and happiness, and darkness and suffering. The Zoroastrians are also the oldest South Asian minority in Britain—with a history going back to 1724. This is the first study of British Zoroastrianism, covering personalities, traditions, and the contemporary concerns of this enduring but little known ancient religion.