Martin possesses two virtues in abundance. First, he’s unapologetically coldblooded. Westeros is a dangerous place governed by the whims of men, not the rule of law, and the first novel in his series is famous for (spoilers follow!) dispatching a thoroughly admirable major character with whom readers have been identifying for most of the book. The killing is shocking, and it’s done on the impulse of a temporarily empowered child. (The same child is poisoned two books later, so hey, all’s well that ends well.) This tendency is less in evidence in “A Dance With Dragons” — in fact, some characters are beginning to seem charmed — but at least one moment in the book will have readers saying, “No way did that just happen.”

Image Peter Dinklage in the HBO series "Game of Thrones." Credit... Helen Sloan/HBO

Martin’s second virtue is a nearly supernatural gift for storytelling. All of his hundreds of characters have grace notes of history and personality that advance a plot line. Every town has an elaborately recalled series of triumphs and troubles. Moreover, historical asides are inseparable from the books’ larger narratives, so as you’re propelled through the story, the sensation is like riding a wave that’s somehow moving away from shore, with the water beneath you growing deeper and more shadowed as your speed increases.

Martin’s finest creations thus far are Tyrion Lannister, Jon Snow and Daenerys Targaryen. Tyrion is a dwarf (a human dwarf, not a Tolkien dwarf), a cynic, a drinker, an outcast and conspicuously the novels’ most intelligent presence. Martin is probably a little too fond of him. Jon Snow is presented as the illegitimate son of the Stark patriarch, although it’s uncertain whether Stark is indeed his father. Jon is a complex, thoughtful and basically good character who leads the Night’s Watch, the garrison of former criminals and landless sons that guards the Wall and that has been reduced to a fraction of its needed strength. Jon’s leadership is the best hope of Westeros, so naturally he’s in imminent danger throughout “A Dance With Dragons.” As is Daenerys Targaryen, the former king’s youngest daughter, who has spent the previous four books in southern kingdoms raising armies to invade Westeros, but who is now slightly sidetracked by her desire to destroy the slave trade. Also, the titular dragons are hers. They turn out to be problematic.

As you can see, there’s a lot going on. And this brings us to the problems with Martin’s books, all of which stem from the very large amount of lot that is constantly going on. This series is long. “A Dance With Dragons” comes in at roughly 9,574,622,012 pages, and smart money says the final two books in the series will make this one look like “The Old Man and the Sea.” Such length isn’t necessary, and it hurts Martin’s prose and his plot mechanics. Tyrion “waddles” at least 12 times here, and even if we suppose the unflattering word reflects Tyrion’s contempt for his own awkward gait, it seems unlikely he would indulge this contempt when he’s, say, fighting for his life. Similarly, when your novel’s terrain stretches across hundreds of miles and your world lacks jet propulsion, as an author you face some basic problems of transportation that can result in conveyance via Rube Goldberg. Over the course of the series, Tyrion has traversed a thousand miles of difficult landscape despite the “waddling,” and this has required at least one ride in a barrel, one ride in a river raft, two boats, one deus ex hurricane and two instances of deus ex coincidental meeting. The second of these meetings, which occurs about midway through “A Dance With Dragons,” involves a secondary character stumbling by accident on Tyrion despite the fact that they’re just about the only Westerosi on the continent. It’s like going to a bar in Suzhou and running into the one guy from the old neighborhood in Hackensack who owes you a beer.

Still, “A Dance With Dragons” is relentlessly entertaining, and it does honor to a best-­seller list previously dominated by the cornball sadism of Stieg Larsson. The question now facing Martin has less to do with how he’ll get Tyrion back to the Wall (an eagle?) than with the complex requirements of his field. Above all else, modern fantasy is the literature of strangeness. Martin’s books, however, are generally praised for their realism. When people are stabbed, they die; when kingdoms ignore debts, the bankers show up. The characters understand their world, and we understand the characters. But this view of Martin’s books is incomplete, because the magical elements of his books are not, in fact, within the characters’ understanding at all — “the Others,” for example, are truly Other. In this sense, “A Dance With Dragons” is a kind of fantasy within a fantasy, and Martin now must find a way to let us feel that strangeness as the characters themselves do, rather than simply explaining it to death.