The Cassini Division by Ken MacLeod

A few hundred years in the future, humanity has divided itself three ways. The first group still inhabits the solar system, governed by anarcho-communism. A second group has passed through a wormhole and lives thousands of light years distant, thousands of years in the future. They are capitalists. The third group has embraced the singularity and transformed into a non-human form. They live on Jupiter and pose a threat to the first group.

The story follows Ellen May Ngwethu, a member of the Cassini Division, a para-military group acting as defense against the Jupiterians. She travels to Earth in search of someone to help her group pass through the wormhole. After various adventures, she succeeds, they make it through, they interact with the capitalist society on the other side, and they have more adventures.

The adventure is nice and all, but the author seems most interested in exploring the ideas. In addition to the several political systems considered, there is also the relationship between humanity and the post-singularity society that has left them behind. Unfortunately, I think, once the ideas are all sufficiently explored, the plot undergoes a rather precipitous conclusion. I was taken aback at how quickly it all just ended.

This was supposed to be a sci-fi reading group discussion topic a few months ago, but due to some communication failures, we haven't discussed it yet.