1928. This volume of studies represents researches spread over a period of many years. Part I: Iranian Religion: introduction; periods in the development of the religion of Iran; Zoroaster, prophet of ancient Iran; Zoroastrianism as a faith; host of heaven; legions of hell; universe and man; moral and ethical teachings of the ancient Zoroastrian religion; eschatology, the ancient Persian doctrine of a future life; religion of the Achaemenian kings; religion after Alexander's invasion, the Parthian dominion; worship, rites and ceremonies, religious observances; relation to other religions; Part II: Zoroastrian doctrine of the freedom of the will; Part III: miscellaneous Zoroastrian studies.