S. M. Stirling’s new series, planned to comprise four novels altogether, has a complicated history. Originally Stirling published the three-volume Nantucket Island series, a “castaways in time” story like L. Sprague de Camp’s classic Lest Darkness Fall, but with not one man, but several thousand people, falling into the distant past. (And nearly two thousand years earlier, in the late Bronze Age!) Then he came back to the twentieth century from which Nantucket had been snatched away, and showed what happened there, in a kind of mirror image series: explosives, combustion engines, and electrical devices all stopped working, and the survivors of the resulting global catastrophe had to rebuild civilization with pre-gunpowder technology. His latest series is a follow-up to those books, set two decades after the Change.

The original trilogy was a story of entrepreneurship, not so much in the economic as in the cultural sense, with smart, strong-willed and lucky people emerging as leaders and founding new communities. This new series is about inheritance, as the children who grew up after the Change begin to take on adult responsibilities, and some of them become leaders. These turn out to be two phases of a process Stirling calls ethnogenesis, the formation of cultures and communities out of social chaos. Where the first series examined a handful of such communities in the Willamette Valley of Oregon, the second has a wider range, as its heroes—the traditional Nine—undertake a quest across what was once the United States.

But something strange is happening as the story progresses. The first book was nearly pure science fiction, examining the engineering consequences of an unexplained natural phenomenon; one could imagine John W. Campbell buying it for Astounding Science Fiction, though without the sexual content. But more and more, the later books are becoming fantasy, and even high fantasy. It’s almost as if J. R. R. Tolkien’s history of Middle-Earth had been reversed, with the rare magic and lesser heroes of the Third Age giving way to the wonders and titans of the First Age. Partly this is because the survivors themselves look to historical models: the medievalism of the Society for Creative Anachronism (hybridized with twentieth century gangster culture), the Celtic traditions of a pagan community, a dash of Viking heroism, two different analogs of the Roman Republic, a Buddhist monastic community, several native American groups, and even a group modeled on Tolkien’s Rangers, created by a teenage fan. As their children grow up, in a world where advanced technology is a fading memory, and older traditions are being revived, they believe in legends, often strongly enough to baffle their elders. But it’s more than that: Stirling shows us what look like prophetic visions, demonic possession, divine intervention, and heroic feats like scenes from ancient epics or sagas.

Central to all of this is Rudi Mackenzie, bastard son of the principal heroes of the first series about the Change, and heir to the chieftainship of his neopagan clan. Stirling showed his birth attended by omens, and his childhood by prodigious feats. Now a young adult, he performs feats worthy of a demigod—for example, leaning sideways on a running horse to lift a full-grown man in armor. In The Scourge of God one of his companions, himself a trained soldier, judges that Rudi is fighting as fast as anyone he’s ever seen, striking blows as hard as he’s ever seen, and striking with amazing accuracy—without having to trade one quality off to get another. And his companions are all capable of legendary feats in their specific domains. On the other hand, these two volumes also show that even legendary heroes can be overwhelmed. In the course of The Scourge of God, both Rudi and one of his twin half-sisters, a member of the Dunedain Rangers, are grievously hurt. And Stirling makes it clear that Rudi is being pursued by agents of a twisted anti-technological religion, who have apparently inexplicable powers, unless the explanation is, as it appears to be, some form of demonic possession.

Meanwhile, back at home in Oregon, the once warring powers are forced to make an alliance against the armies of that same cult, and old adversaries find themselves working together. And in this part of the story, too, there are dreadful injuries, and some deaths. Stirling’s one of the best writers in the science fiction/fantasy community at describing military action, at conveying the complex factors that determine its success or failure, and at making it emotionally real. Each of his cultures has its own distinctive martial arts and its own preferred weapons. And another major theme of these books is the ethics of war. Stirling is no libertarian, and certainly no anarchist; his characters are rulers, in a society where rulers use force, or directly command those who do. But his heroic characters use force to defend innocent people, shielding them with their own bodies against criminals and tyrants. In his legends, the king’s ultimate role is not to rule the people, but to die for them.

These are adventure stories, but some solid thought has gone into them. I compared the first series to Poul Anderson’s Orion Shall Rise, with its tapestry of cultures evolving after a nuclear war. In this second series, Stirling adds more well-thought-out cultures to the tapestry, showing the combination of historical necessity and lucky accident that shapes them—for example, the Lakota who took in a Mongolian exchange student after the Change and learned some useful things about traditional Mongol technologies. There are a few scenes where I think his judgment could have been improved, but I find these books intelligent entertainment, with good characters, an interesting theme, and a compelling mystery. I look forward to the rest of the series.