Will the Holocaust ever be ­history? Unlikely. Ayatollah Ali Khamenei has just written a book in which he doubts the Holocaust happened. “If there was such a thing,” he writes, “we don’t know why it happened and how.”Perhaps Timothy Snyder’s new account of the Holocaust needs to be translated into Persian to persuade Khamenei it did happen and was conceived and carried out by educated Europeans – it is surprising how many lawyers became SS officers. These were not just Germans: willing exterminators came from France, Poland, Serbia, Ukraine and the Netherlands.Snyder does not produce new material or suggest a completely revisionist account, so much as weave together previous research, including his own, into a new narrative, ­making s