This systematic treatment of Zoroastrianism is edited and translated by Emeritus Professor Mary Boyce, a noteworthy modern authority on Zarathushtrian Studies, including its influence on other religions. A copious introduction featuring charts, maps, and illustrations of, among other things, the ancient Iranian 'world picture', a chronological background to the texts, and the Zoroastrian 'world year' provides the perfect starting point to understanding this largely invisible religion.