Humankind has expanded out into interstellar space using star gates-technological remnants left behind by an ancient, long-vanished race. But the technology comes with a price. Among the stars, humanity encountered the Fallers, a strange alien race bent on nothing short of genocide. It’s all-out war, and humanity is losing.

In this fragile situation, a new planet is discovered, inhabited by a pre-industrial race who experience “shared reality”-they’re literally compelled to share the same worldview. A team of human scientists is dispatched-but what they don’t know is that their mission of first contact is actually a covert military operation.

For one of the planet’s moons is really a huge mysterious artefact of the same origin as the star gates . . . and it just may be the key to winning the war.

I found the ideas in ‘Probability Moon‘ intriguing but the writing was a little dry until almost the end of the book. Oddly perhaps, it was the humans in the story who I had difficulty engaging with. I eventually became quite engaged with Enli, the main alien character.

The humans are split into two: a four-person team of anthropologists down on the planet ‘studying’ the indigenous culture’s concept of ‘shared reality’ and a military ship carrying out the real mission – to acquire what is believed to be an ancient alien weapon in orbit around the planet.

The military mission was more interesting for the physics being discussed and for providing the background on how the interstellar human diaspora, enabled by a network of ‘gates’ built by an ancient, now vanished, race are at war with an alien species who use the same inherited technology and who no interest in anything except expansion and extermination. The military characters were an unconvincing collection of stereotypes whose main function seemed to be to exposition.

The anthropologists were more interesting. I’ve never seen classic Persian poetry used as a reference for divining the meaning of events on an alien planet before in the way the Iranian team leader did. There was an American character with an undiagnosed God complex, a woman xenobiologist who seemed to be there to explain the physical differences between humans and aliens and a large jovial German geologist who was the easiest to like and also the least introspective.

 At first, I couldn’t see any connection between the two human missions. It took longer than it should have done to see that the book title was a clue to the concept behind both military and anthropological missions. This concept linked the apparently sociological phenomenon of Shared Reality with the observer effect in quantum mechanics.

The thing I liked most about the book was seeing the world through Enli’s eyes. I liked that when I first met Enli, she was an outsider in her own culture. I quickly learned that she was ‘Unreal’. Understanding what that meant and how it worked was, for me, the most interesting part of the book. I thought that Nancy Kress did a great job of making human behaviour seem odd by establishig Enli’s people as a baseline for normal.

I enjoyed the ideas in the book but I couldn’t engage with the human characters. I wasn’t invested in the outcome of the military mission, even when the crew was at risk. The anthropologists were interesting mainly because they demonstrated how hard it is to see another culture clearly when you are unaware of the blindspots created by your own cultural biases.

‘Probability Moon‘ is the first book in a trilogy but I won’t be moving on to the other books. I think these stories at too abstract for me.