Pratchett, Terry and Stephen Baxter. The Long Earth

Everyone remembers where they were on Step Day—the day the plans for Stepper devices leaked onto the internet and every child who built one discovered that the Steppers allowed them to travel “sideways” to the next parallel Earth next door. The world changed forever on Step Day, as endless new frontiers opened with the flip of a switch. Joshua Valiente was only 13 on Step Day, but he took to Stepping like a fish to water, experiencing none of the disorientation and nausea that struck almost everyone else. Since then, he has traveled further than anyone else he knows of, and has even discovered that he doesn’t need the Stepper device but can Step on his own. A loner by nature, Joshua is skeptical at first when he is approached by the artificial intelligence named Lobsang who wishes Joshua to travel with him to the farthest reaches of what’s now known as the Long Earth, but in the end the lure of the unknown is too great to resist. As they two travel further and further into the parallel worlds, things become stranger and stranger, and they begin to realize that something out there is threatening the stability of the entire system and only they have the wherewithal to stop it. Meanwhile, back on the “original” Earth, the political and economic system, already destabilized by Stepping, quickly approaches a cataclysmic collapse.

Readers expecting another Discworld will not find that here. While The Long Earth shows flashes of Pratchett’s wit and inventiveness, it is a very different beast altogether, with a much more serious, sci-fi tone. One hopes that future sequels will delve further into the unusual ecosystems of the Long Earth and continue to flesh out the characters of Lobsang and Joshua.