"The Dawn and Twilight of Zoroastrianism" R. C. Zaehner, 1961
"Of all the great religions of the world Zoroastrianism presents the most intractable preoblems; for it was a religion founded by a prophet who claimed to have a revelation from the one tur God and who nonetheless lived in a tradiionally polythesitic society not yet ripe to receive the totality of his message." First American Edition of a rare and intersting work.