In his book, The Dawn and Twilight of Zoroastrianism, Professor R. C. Zaehner gives as an appendix Professor W. B. Henning’s critique of the work of E. E. Herzfeld and H. S. Nyberg, taken from Henning’s Zoroaster, Politician or Witch-doctor? (Oxford, 1951). It is much to be regretted that this appendix did not include the whole of that valuable short work by Professor Henning; rather than comprising only the part of it which is least tasteful and of least interest to any but those few who are arrayed in the ranks of quarrelling Zoroastrianists. Because it is to Henning’s lucid description of who Zoroaster was, where and when he lived and what he taught that the wearied and somewhat confused reader of this much larger work by Professor Zaehner wants gratefully to turn after the ordeal he has just undergone. However Professor Zaehner does satisfy the enquirer on the matter of when Zoroaster lived: he follows Henning and dates Zoroaster as Zoroastrians have traditionally done—‘258 years before Alexander’ ,i.e., Alexander’s defeat of the Achaemenids in Iran in 330 B.C., so that Zoroaster’s date may be taken as about 588 B.C. This is important because of theories which have been advanced, that Zoroaster lived much earlier; and that he lived at all has, also, I believe been put in doubt. Therefore it is refreshing to have a Henning and a Zaehner, who know the languages and the texts relative to Zoroastrianism and the prophet’s original teaching, to tell us when he lived—not so long ago after all— and also where.