OK, after a few breaks, I've finally finished this book, which is a record for me, I'm usually a fast reader. It really dragged in the middle, and is not an easy read, but was still fascinating nonetheless. It's not just one story, there are at least three that are obvious, and probably even more beneath the surface.
It's worth hanging on to the end, though, once all the threads get wrapped up, or reasonably so, it really does make sense.