A story in three sections, and the first is barely science fiction. Mostly politics, with a MacGuffin that gives free energy - or is it free? This book won a Nebula, a Hugo, and the Locus SF award, and was regarded by Isaac Asimov as his favorite book.

The second section is a very alien world, with the connection only visible near the end. The third section brings the whole story together quite well, though I found myself thinking of [b:The Moon is a Harsh Mistress|16690|The Moon is a Harsh Mistress|Robert A. Heinlein|https://images.gr-assets.com/books/1348768309s/16690.jpg|1048525], written six years earlier. Do all lunar colonies have intrigues and rebellions?

Keeping this from five stars for me was all the dialog to tell the story. There isn't a lot of action. How many other books did Asimov use a three part structure for? It turns out this was published serially in Galaxy Magazine, so that at least makes sense here. I am not sure I would have continued past the first in that format, it so lacked in sci-fi.

I am glad that it ended up on my list in book form, and also glad I finished it.