Back in 1985 that set the tone. Mongolia. Utterly out there. Grass. Ponies. Wrestling. Forgotten. Of no importance. Genghis Khan maybe. A brute. Otherwise, a place consigned to geographical oblivion in the minds of most.

That was then. Now, thanks in large part to the restored reputation of Genghis and the many successor Khans — a restoration achieved in no small part thanks to the literary diligence of Jack Weatherford — Mongolia has come roaring back, being currently a highly modish place to visit (tourism has tripled in the last decade), a place to revere, be amazed by and in awe of. As a minuscule country that for a few shining centuries — rather like Britain, six hundred years later — expanded and held sway around a goodly part of the globe, from Vietnam, Burma and China to Hungary, Thrace and Poland.

Weatherford (an anthropologist whose fathomless wellsprings of curiosity once led him to clerk in a Capitol Hill porn store to write a book that remains discreetly unlisted on the Also By page here) would like us to believe that those centuries of Mongol rule did indeed shine, and were, as far as imperial adventures go, among the best of their kind.

It was in an earlier best-selling volume that Weatherford persuasively argued that the 25-year blitzkrieg mounted by Genghis and his cavalries — who, in “the most extensive war in world history” beginning in 1206, swept mercilessly and unstoppably over the Altai Mountains to their west and the Gobi Desert to their south — brought civilization, fairness, meritocracy and avuncular kindliness to legions of undeserving satrapies across Eurasia. Those who believed Genghis to be a tyrant of monstrous heartlessness have thus lately come to think otherwise: Weatherford’s writings present us revisionist history on a grand scale, but one as scrupulously well researched (with ample endnotes) as such an intellectual overhaul needs to be.

Now, with “Genghis Khan and the Quest for God” he has taken his thesis still further, arguing with equal fervor and conviction that the Khan, though godless himself, favored total religious freedom for his subjugated millions. While his empire encompassed “Muslims, Buddhists, Taoists, Confucians, Zoroastrians, Manichaeans, Hindus, Jews, Christians and animists of different types” (Weatherford’s passions for lists can sometimes seem like stylistic overkill), he was eager that all should “live together in a cohesive society under one government.” No walls to be built, no immigration bans, no spiritual examinations.