The Long Earth is a great idea – humanity suddenly gains access to a potentially infinite, mostly unoccupied string of Earths, each a sidestep along the potential outcomes of all the possibilities that formed this Earth. It’s not time travel (sadly) and it’s not alternative universes (exactly), but it is a fascinating fictional exploration of a number of the scientific ideas about how Earth and all its ecosystems got to, well, here, and what might have happened if we hadn’t. It's also got great SF cred: a collaboration between Terry Pratchett and Stephen Baxter (disclaimer: I don't recall reading any of his works, although I might've) should, by rights, produce an exciting, slightly comic and very human story with a cosmic scientific awareness to back it up.
Unfortunately the authors seem a little too fascinated with their own great idea – there is a thread of a plot (a quest, of course), and attempts at creating suspense, but these are sidetracked by the temptation to show off the world and all the work that went into it. It’s as if they couldn’t bear to cut out any of the interesting creatures (look, a flying octopus! - no, really, there’s a flying octopus) or ideas (a cult of comedic atheists!).
The exploration of the idea is the strong point of The Long Earth. It doesn’t stoop to stereotype in looking at how the world changes, but has plausible and interesting considerations of the impacts on social, economic and political structures, as well as the practical ways that people would react and adapt. These are all at higher levels though – countries, cities, police forces. Up close to any of the characters, they seem concocted from the basic fantasy recipe book: for the perfect loner hero, take one orphan, add quirky upbringing and secret talent, stir and allow to develop for ten years. I tried to drop my expectations of a Pratchett book before coming to this one, but was surprised that the usual depth and dexterity of his characterisation was missing from so much of it.
The thin deus-ex-machina quest attempts to anchor the story as we wash back and forth through recent history and across the multitudes of Earths, various side stories spinning off as we pass. Often I was more interested in those side stories, but some never develop, and others work away behind the scenes, their resolutions mentioned chapters later, in passing. Some seem to exist merely to fill narrative gaps: we’ll need bronze here, so we need a forge there, so let’s introduce this guy back here. Tick.
My main frustration with The Long Earth is that it is an ok story about this well-constructed and original world, when it could have been a great story set in this world. A rip-roaring quest, an intense exploration of family and social dynamics in times of change, a series of inter- and over-lapping short stories (ala I, Robot) shifting between that and more... the breadth of worlds provides an awful lot of scope. Instead it’s a thoughtful, reasonably interesting, semi-scientific exploration of what made our Earth what it is, (with an unfortunate and unoriginal diversion into the origin-of-elf-stories trope) let down by some unnecessary weak points*, not quite knowing what story it wants to be, and an incredibly weak ending. It’s barely an ending at all, in fact - it turns out that this is only half of the story and I have been suckered into breaking my GRRM rule.** After a flaccid attempt at resolving the quest enough to finish the book, but leave things open for a sequel, the story just stops. Seriously. I’m trying not to include any spoilers here (the book is only a few weeks old, after all) but there is no ending, no climax, no great revelation or cliff-hanger. It.
*you’re in a fight with something that can step between worlds and is attacking you from those different worlds, but though you can change worlds yourself you don’t, even to run away – if I’m picking up issues with fight scenes, they must be pretty bad.
** Which is: Never start a series until the author has finished it and any sequels associated with it. I thought about calling it the Robert Jordan rule, but 1. he died, and it wouldn’t be very respectful, and 2. RJ had the end in mind, whereas GRRM has wilfully started multiple series without knowing the end, which I think is potentially fraud.