Like The Steerswoman's Road this trilogy shows us what we call technology so that it looks like magic; but this is not fundamentally a rationalist novel. It may, like The Lord of the Rings, be more of an epic than a novel. I kept thinking of in comparison, and not just because I was deciding if author Rohan had matched his model; there are a bunch of places, chiefly the embodiment of magic, in which I think Rohan decided to solve a problem Tolkien had in a different way, which was neither better nor worse.
Tolkien's prose does beat him hollow for flexibility; Rohan-author has a slightly formal, highflown style that holds its tenor better than almost all adventure fantasy, but it's only one style. There's nothing like the change to poetry that Tolkien used in, coincidentally, his description of Rohan.
The Winter of the World is most flexible when mixing fantasy and science; a little like , with utterly different purpose. The whole plot is the coming of the last Ice Ages, and the geology and geography is joyous. But in this book the Ice Ages are caused by a battle between gods, and the gods take physical form and are affected by them. Similarly, the details of some of the magical works slip from pretty-much-science to a fistful of fusion, and very gracefully. The other background is North European myths, and the three twine when we get a sort-of transition from magical dwarves to Neanderthals.
My favorite bit is that the hero, a smith, spends decades of single-minded, often solitary, toil learning his craft even though he is chosen of the gods. It's not that the gods couldn't install the skill, if one assumes gods; it's that it makes a damned dull novel, and if you're going to have actual characters they'd better have to work for their skill.
My least favorite bit was the conflation of anti-aristocratism with ultimate evil. Given the gods and mythology, aristocratism is to be expected, but I thought it was not only excessive but surprisingly bad storytelling to make the representative republican carry quite so many flaws. He'd have made more sense as a minor and deluded villain.
Find in a Library: The Anvil of Ice
So wrote clew in SF&F.