Marion G. Harmon, A Writer in Vegas.

I’ve been a Terry Pratchett fan since high school and The Color of Magic. The scene where Death offers Rincewind a fast horse so he can make it to their scheduled meeting, will forever remain one of fantasy-humor’s Great Moments, and Pratchett’s wit only got sharper over the years. Unfortunately, to some degree, Terry Pratchett has become the victim of his own success; it is now almost impossible for him to write serious fiction. And this is a serious work in every meaning of the word.

How many times has our conceptual paradigm been shifted? When we moved the Sun to the center of our universe. When we realized how big our universe was and how far from its center we were. When scientists figured out a theory of life that didn’t require God. Our technological paradigms have shifted more often; electricity, vaccines, combustion engines, antibiotics, wire and then wireless communication, flight, x-rays and organ transplants, computers, etc., have all changed our worlds. Conceptual paradigm shifts are sudden, but take years or decades to work through the permutations; in a free market, technology shifts are often much faster, and seriously change the way we live.

Take my experience with writing, for example. I attended college, with a couple of small breaks, from 1984 to 1995, picking up a double-BS and an MA. When I started college, electric typewriters were cutting edge, then “word-processor” typewriters. The first Apple Computers were out, but printers were crap, and I remember writing essays in pencil and then typing them up in a dungeon beneath the library. The library upstairs, and interlibrary loan, were my only sources of research material. Now? Now I draft, first to last, on my keyboard. I send copies to beta-readers. I research streets in New Orleans by walking down them using Google Maps, collect background through Wikipedia and other sites, and pretty much treat the whole world as one big open book. I sell thousands of copies of my books, digital and print, without ever signing a publishing contract.

And that is only one way the Information Age has changed the way we live.

So what does this have to do with The Long Earth? The point is that serious science fiction, unlike sci-fi adventure or sci-fi fantasy, asks the Big Questions. How will discoveries change us? What would easy space travel mean? What would immortality mean? What would an economy driven by material fabrication and robot-labor mean? What if we really met E.T.?

In The Long Earth, Terry Pratchett and Stephen Baxter posit a paradigm-shifting invention, a “stepper.” Easy for anyone to make (you can do it with Radio Shack components and a potato), the stepper allows you to step into the endless chain of parallel worlds to the right and left of our reality. And other than some illusive and mysterious world-stepping hominids, these worlds are empty–at least of intelligent life.

So, if we had access to steppers, if each step took us to a new world, each new world one step different than ours, what could we do? What would we do? First the positive: we could stop worrying about resource depletion; we are never going to run out of resources or room. And speaking of room, suddenly we have room to leave; if we don’t like the current state of society, we can go off and found our own. There is room in the Long Earth for the utterly antisocial to wander away into worlds where he will never see another human being, ever.

But are there negatives? Of course. For one thing, not everyone can step easily (it makes most people vomit or at least have to sit down for a while, and a significant minority can’t step at all), so as with all technologies, its direct benefits are unevenly distributed. There are other downsides, and you’ll have to read it to find out. I strongly recommend you do.

Because here’s the thing. We live in a world where conceptual and technological paradigm shifts have accelerated. Cellphones, computers, medical science, energy production, each decade seems to be a quantum leap beyond the one before, while our understanding of the Very Small and Very Big changes almost as quickly. What will happen to our world when we learn how to extend our lives a century or more? Or download our brains? Or move to a Total Automation economy? Or build the space-elevators or sky-hooks that will allow us to economically conquer the Solar System? On a more personal level, what will happen to society when we achieve 100% effective and universal birth control and develop artificial wombs?

We change our world, and our world changes us. The Long Earth tells the story of a Big Change. It’s an unlikely one, but like most What-Ifs it says more about us than it does about the imagined scenario. It’s a story about humans, individuals and societies, reacting to and adapting to change. Because it’s about us, it shows the Good, the Bad, and the Ugly. And because it’s by Pratchett, it’s a freaky and fun read.