I bought this right after reading Primordial Threat. While the universe is the same, it isn't really a close follow-on. A fair period of time after the events in the previous novel, we find an Earth well-adjusted to its new home, and globalized to the point of all citizens' lives being monitored and regulated - for their own good, and the general safety of society, of course.
All would be well, except for those pesky rebels, who are just not quite within the grasp of the UN.
The previous book reminded me of Niven - this one of Heinlein's Harsh Mistress. Pretty high praise, but I think it's due.
You don't have to read the first book before you get to this one... exactly. But you should.