THE HISTORY OF STEAMPUNK is a strange one, full of odd detours and byways. Author K.W. Jeter coined the term in 1987, when he noticed similarities between his work and those of his fellow Los Angeles writers Tim Powers and James Blaylock. All three had written novels set in the nineteenth century. All three — especially Jeter and Blaylock — made use of maniacal inventors and outdated Victorian science, the technology of steam and gears and clockwork. All three wrote in what Jeter called “the gonzo-historical manner.”

But if Jeter had been trying to create a movement, something on the order of cyberpunk, he would have been disappointed; very few people answered his call. There were a few other steampunk works written around this time, notably The Difference Engine by William Gibson and Bruce Sterling, and John Crowley’s wonderful novella “Great Work of Time,” but for the most part the movement slumbered or went underground for two decades. Then, suddenly, it re-emerged nearly fully grown, stronger and more popular than ever, in the twenty-first century. Almost overnight, it seemed, there were conventions, costumes, customs, iconography, artists, and musicians — and, of course, writers.

Science fiction had changed a good deal since the 1980s, though. For one thing, it had undergone a fairly serious crisis of conscience, when it had looked around and realized that, for a genre so concerned with the future, its practitioners and protagonists were for the most part male and white. Almost as soon as steampunk appeared, or reappeared, it was attacked on these grounds. Because it valorized the Victorian age, critics said, steampunk was inextricably mixed with imperialism, classism, sexism, and racism.

Charles Stross said it better than anyone else:

 We know about the real world of the era steampunk is riffing off. And the picture is not good. If the past is another country, you really wouldn’t want to emigrate there. Life was mostly unpleasant, brutish, and short; the legal status of women in the UK or US was lower than it is in Iran today: politics was by any modern standard horribly corrupt and dominated by authoritarian psychopaths and inbred hereditary aristocrats: it was a priest-ridden era that had barely climbed out of the age of witch-burning, and bigotry and discrimination were ever popular sports…. It was a vile, oppressive, poverty-stricken and debased world and we should shed no tears for its passing [italics are Stross’s].

And of course this criticism is certainly justified in some cases. (You’ll notice that all the steampunk authors I mentioned earlier are white males.) But while the ink was still drying, or the pixels fading, on these charges, steampunk was showing just how flexible it could be, changing and reinventing itself yet again. Just because so many of its stories had been set in the Victorian era, its practitioners thought, there was no reason you couldn’t set your story somewhere — anywhere — else. Just because so many protagonists were the white male scientists of nineteenth-century England was no reason you couldn’t feature someone — anyone — else. These were alternate worlds, after all, worlds limited only by the imagination.

Cherie Priest is part of this second wave, publishing her first steampunk novel, Boneshaker, in 2009. Almost immediately, she signaled that her novels would be different from the usual fare, that her sympathies were with the people who, until fairly recently, had been left out of conventional histories. There is an inventor here, but it was his invention, the Boneshaker of the title, that caused the catastrophe of the novel, when it dug too deeply and released a horrible gas called the Blight. But he’s a fairly shadowy figure, and instead Priest concentrates on his wife and son, Briar and Zeke Wilkes, who venture into the poisoned area he has created in search of him. In her choice of setting, too, she ignores what Stross called “wealthy aristocrats sipping tea in sophisticated London parlours” and instead situates her novel in late-nineteenth century Seattle.

The Inexplicables is the fourth novel in this series, which Priest calls the “Clockwork Century.” An enormous wall has been erected around the part of Seattle contaminated by the Blight, and by the opening of The Inexplicables, the people living there have even developed a kind of society, sealing off some parts and wearing gas masks when they have to venture outside. It still isn’t completely safe, though — trapped with them inside the wall are the shuffling undead, the rotters.

Her protagonist this time is Rector Sherman, who has grown up in an orphanage, his parents victims of the Blight. On his eighteenth birthday the orphanage throws him out, leaving him to make his own way in the world. Earlier, he showed Zeke Wilkes how to get into the walled area, and now he is certain that Zeke is dead. Haunted by Zeke’s ghost, he follows him into the society beyond the wall.

Rector begins as an unlikable lout, and unfortunately he doesn’t improve all that much over the course of the novel. He steals things, he’s mean and whiny and selfish, he uses people. (“He had a long-standing policy of being nice to smart people, in case they could be useful to him later.”) And, as if that isn’t enough, he also has a drug problem. It’s a risky authorial strategy. We have to see past these surface traits to Rector’s core, to sympathize with his rough upbringing in an orphanage and his problems in the strange world that Seattle has become. This proves difficult at the best of times, and when Rector complains yet again about something, you want to hit him over the head with a heavy object.

Once inside the wall he comes face-to-face with a huge creature that is neither human nor rotter (the “inexplicable” of the title), and he is hired by his drug supplier, Yaozu, to find out how some outsiders are managing to breach the wall. He discovers that these outsiders belong to a gang challenging Yaozu’s drug monopoly, and the people within the wall decide to join Yaozu to fight them; he is at least someone they know, and is working to make their lives better.

It proves to be fairly simple to overcome the rival gang, though, and to capture the inexplicable. In fact, the lives of everyone within the wall seem a good deal easier these days; the freewheeling anarchy of an earlier time is gone. The rotters are disappearing, the inexplicable is not much of a threat, and even the drug lords are settling down. The danger and excitement of the earlier novels, the sense of discovery, are missing here.

Rector also learns that Zeke is still alive, so his reason for heading inside the wall doesn’t make a lot of sense: Why was he so convinced that Zeke was dead? By this time we have discovered that Rector had another purpose in braving the wall — he wanted to find Yaozu and start dealing drugs — so the earlier emphasis on Zeke’s ghost seems misplaced, a complication that goes nowhere.

Fortunately, the novel has compensations. These come mostly in the form of a travelogue, a tour of post-Blight, post-zombie Seattle, a place shot through with weirdness and enchantment. (The rotters, for example, don’t climb upward, so many of the pathways are stairs and bridges from one building to another.) Priest describes the place as if she has lived there, dismembered bodies and unpleasant smells and all: “He took a deep breath. It stung, and it filled his throat with the taste of rubber and powdery black filters…. His warm, dank breath made the visor briefly foggy.” Her characters, as always, are a diverse group, Chinese immigrants, native American princesses, old women, children. They have very little, but their harsh existence has taught them to share what they do have, to help each other out. Their lives, in fact, come closer to what is called Dickensian than many steampunk novels that use Victorian London as a backdrop.

And if Rector is hard to like, Priest makes up for it with the friends he finds within the wall: Zeke, a shy boy who likes animals, and Houjin, who becomes Rector’s guide. Even Rector begins to show some promising signs of empathy at the end, and he weans himself off drugs, though not much is made of this.

A large part of The Inexplicables, in fact, reads like a set-up for the next installment in the “Clockwork Century”; the Epilogue consists almost entirely of unanswered questions, and the brief appearance of the inexplicable has to be a set-up for later adventures. Will Rector grow out of his selfishness? Has he stopped taking drugs for good? If Priest returns to her earlier fast-paced, adventurous style, it will be interesting to find out.