Divergence sees Tony Ballantyne continue to build upon the world and the characters first introduced in Recursion and Capacity, via another complex, braided, and multi-book plot resembling the ‘n-string game’ that first appears on page 78.

Divergence begins in the year 2252, introducing the dysfunctional (a more unkind person might say 'incompetent') crew of the spaceship Eva Rye, a motley bunch feeling their way out into a universe they barely know, let alone understand.  Meeting a mysterious stranded stranger who offers to trade with them via an equally mysterious 'Fair Exchange' computer program, the crew takes on board a peculiar woman, Judy.  In exchange for her passage to an embattled Earth the stranger sorts out the problems aboard the Eva Rye – although not in the manner anticipated.

In the wider universe, the Watcher, humanity's beneficent AI overseer on Earth, is under siege from both another AI and an infestation of deadly Dark Seeds, a strange, yet apparently natural, quantum phenomenon.  As if there weren't bad enough news for both the Watcher and a perfectly ordered and happy humanity, Judy has been told that upon reaching Earth she will kill the Watcher, even though she can't imagine carrying out such a terrible deed.  Can this unwilling mission be related to her flashbacks of being the actual original Eva Rye on Earth in the year 2089, trying perversely to escape the attentions of a fledgling Watcher in the Russian Free States?

It's a question that pervades Divergence: why would anyone not want to be part of a world and a population shaped for perfection?  Why not hand over control of your destiny to a brilliant and entirely benevolent super-intelligence?

I did begin to wonder if, at its core, Divergence isn't a book-length questioning of Banks' Culture, which has also handed over control to brilliant and entirely benevolent super-intelligences (albeit on a larger scale).  If it is, then the conclusion eventually reached here is a repudiation of Banks' anarchist Mind-run utopia.  Admittedly it's easier to reach such a conclusion if you're writing in a more Dick-ian, not to say anthropic mode, as Ballantyne seems to be.  His strange universe initially seems to owe more to Cordwainer Smith than Dick, but don't be fooled: Ballantyne's novum is a more fluid affair than either Smith's or Banks', and far less restricted by any kind of need for Hard SF explanations and justifications.  Here, just as in Dick's hallucinogenic worlds, spaceships, AIs and Von Neumann Machines are simply a given - which makes a perverse amount of sense given that most of future humanity in the Ballantyne universe doesn't seem to understand how anything works either.  However, Ballantyne has greater forces at play than mere Culture Minds, and while Divergence often seems to be adrift in a sea of random events, there is a perceivable method to his madness.  This may be as godless a universe as Banks', but is not without its teleology.

Divergence is a strange little book; it begins simply enough, chock-full of all the traditional SF ingredients, a straightforward space adventure almost reminiscent of the pulps in its charming naivety.  But Ballantyne does an excellent job of twisting this around, dribbling in a few extra unexpected spoonfuls of thoughtful philosophy and abstract concepts, until you're about as far away from ray-guns and bug-eyed monsters as it's possible to get and still be in a spaceship!

So this strange little book isn't for fans of old-style space opera.  Reminiscent in style of M. John Harrison, and in some ways the plot of John Clute's Appleseed, I can give little higher praise to a book's intellectual ambition.  But is there the mortar of a good story surrounding the bricks of its philosophising?  Well, yes, mostly there is; not to mention robots with disintegrator guns, Schrodinger's Kittens, AIs called 'Kevin' and 'Chris' and the brilliantly scary Dark Flowers.  It's all somehow wonderfully English: drifting slightly off kilter and out-of-control – but not too much!.