Rather surprisingly for Modesitt, there's practically no mention of the environment and ecology in this book. There's also little put forward regarding how a future society should function. There is, however, plenty of talk about, or in fact against, religion, as well as much about certain other defining characteristics of humanity, so it's certainly still Modesitt, largely wrapping philosophy in space opera in order to get some ideas across to a wider audience.
What I can say about the book is that I liked how it went perhaps somewhat into Rama territory but had next to nothing of the human filth that made me loathe those books. Or it still had a fair bit of it, seeing what its purpose was, but it was presented in a way that I could not just stomach but actually even enjoy, mostly. And the contrast between Chang's and Fitzhugh's chapters was quite refreshing, as were the four different viewpoints in general.