Ken Macleod's socialist science fiction universe gets a lot clearer in 'Dark Light', the second novel of his 'Engines of Light' series. This time around, he focuses his story on Croatoan, the sister world to Mingulay in the "Second Sphere", a region of inhabited planets created by godlike aliens for unknown reasons. In the conclusion of 'Cosmonaut Keep', Gregor Cairns managed to create a technology that allowed humans to pilot a starship, a feat that had previously been the sole province of the mysterious, aquatic Krakens. The feat might bring new life to the Second Sphere, and enable the races who have been brought there to understand to what purpose they were kidnapped from their home worlds. Is the Second Sphere all just a giant 'fail-safe backup' in case there is catastrophe in the home worlds? Or is it something else, beyond human -- and alien --ken? The mysterious gods, distributed intelligences that exist in cometary dust swarms are the only beings who can answer that question, if they choose to do so. But Gregor has chosen Croatan as a destination for all too human reasons -- to follow the woman he loved briefly in her trading visit to Mingulay. When the human-piloted Bright Star lands on Croatan, its presence is even more controversial than the occasional visits of the star traders piloted by the Krakens and manned by the humans. The question rapidly evolves as to whether or not Macleod can marshal all the threads he's created and bring them together in a satisfying novel that doesn't complete the overall story arc of the series.

To help himself and his readers, Macleod tells the story in a simple, linear fashion, eschewing his usual method of entwining story lines that intersect in a revealing finale. But seemingly nothing can keep Macleod's speculative imagination reigned in, and this is one of his great strengths. In 'Dark Light', the inhabitants of Croatan take center stage with the Cairns and the crew of Bright Star. Macleod uses the opportunity to muse at length about sexual identity and roles as he creates a society where sexual roles are chosen, not confined by sex. In the society of "heathens", taken from earth in time immemorial, men can choose to live like women, and women to live as men. Stone is a man who has chosen to live as a woman, carefully mending the gliders that help drive the heathen economy. Macleod is extremely successful in parlaying this character and his action into a fascinating inversion of current sexual identity and mores, using him to drive the plot as the crew of Bright Star tries to recapture their starship, which is immediately impounded upon landing in the very Christian community of Croatan. No mystery where and when they were taken from!

But Macleod does not confine his speculation to sexual identity. You can count on some excellent political theorizing, and here he's in absolute top form. In one sequence, the laborers of Croatan as discussing their planetary assembly (representatives are chosen by drawing of lots), with this priceless interchange:

"'We've been discussing, just throwing ideas around, you understand, just considering the notion that it might be a good idea some time in the future to change the constitution so that neighborhoods meetings elect the delegates, to ensure that the majority view prevails beyond cavil.'

The two men nodded firmly. Gail looked shocked.

'What about minority views? Who would represent them?'

Endecott made an impatient chopping gesture.

'Oh, the minority would be bound to get some delegates, and anyway they'd be quite free to try and become the majority themselves. I don't see how it could be a problem. Like you said about drawing lots, it all comes out in the wash.'

'That's ridiculous, that's completely different,' said Gail. Drawing lots is fair, even if it sometimes throws up a freak result. With elections you're actually building the minority problem right in at every level, and lots more with it -- parties, money, fame, graft, just for starters. What chance would that leave ordinary people, what chance would we have of being heard or making a difference? Elections are completely undemocratic, they're downright anti-democratic. Everybody knows that!'"

There are a number of moments of this nature, with subject ranging from labor and the economy to the influence and nature of gods. This time around, Macleod lets Matt Cairns lead the action, as he spars with fellow immortal Volkov in trying to shape the politics of a world neither has lived in or is particularly interested in staying on. The new characters, Stone and Gail, are particularly interesting, but the readers of 'Cosmonaut Keep' are likely to feel that Gregor Cairns and Elizabeth Harkness are getting the short shrift. Fortunately, the pot-smoking Saur Salasso is around to keep things in perspective.

Macleod is clearly working on a wide canvas here -- each of the books is labeled as part of a series and 'Cosmonaut Keep' must be read before 'Dark Light'. Theoretically, everyone is being set up for something 'up the line', a phrase that comes to have an ominous meaning in this novel. Again, for a certain subset of readers the social and political factionalism will seem like a murky mess rather than the blur at the edges of a huge universe. Even so, there are enough delicious ideas and subtly humorous jabs in the 'Engines of Light' books to make them worthy of your time. At 292 pages, 'Dark Light' is briefer than even a portion of other serial science fiction novels. Yet it's richer in ideas and quirky character interactions than many a book-brick taking up shelf space in libraries and bookstores.