The Long Mars

It has been fifteen years since Yellowstone erupted on the Datum, gouging the heart out of America and plunging the world into a volcanic winter. Emigration to the worlds of the Long Earth has increased, and the population has become attenuated, stretching out across the near-infinite space of the stepward worlds.

The ur-pioneers Joshua Valiente and Sally Lindsay find themselves once more roped into adventures not of their own making. Joshua is recruited by the AI Lobsang to investigate the apparent rise of an intellectually superior subspecies of human, while Sally's father - Willis Lindsay, father of stepping - calls on her to accompany him on a mission not just to Mars, but to The Long Mars (roll credits.) Meanwhile, US Navy captain and veteran explorer Maggie Kaufman is sent out to delve deep into the Long Earth. With two 'Twain' airships and a crew of navy personnel and scientists, her goal is to travel a quarter billion steps from Earth, into worlds as alien as any Mars.

As with previous books in the Long Earth cycle, The Long Mars is a multi-stranded narrative with a somewhat take-it-or-leave-it approach to the conventions of dramatic closure. The main narratives are Sally and Maggie's, with Joshua's primarily serving to set up the final conflict which bring the two other threads together, and the dominant theme of the book is that of the alien. This theme is expressed in the many Marses which exist in their own long chain, distinct from the chain of the Long Earth and only crossing at the Earthless Gap (which may mean that a) every Earth's Mars connects to a different Long Mars, b) every Mars's Earth connects to a different Long Earth, or c) that the Long Mars and Long Earth intersect entirely, but not in a fashion which line up with one another,) but also in the remote Earths which developed in a radically different fashion to the Datum, and the thought processes of the Next.

As in The Long War, the science in The Long Mars is better than the fiction. Although written as a conventional narrative, it has more of a documentary quality to it, leading to an open ending and a lack of really likable characters. Again in common with the previous book, the most sympathetic character is a semi-outsider, aging rocket jockey Frank Wood. In the nature of high-concept hard SF, the resulting novel is more interesting than involving (I think I said the same thing about much of Neal Stephenson's oeuvre,) but it is definitely interesting.