I'm a student, so I don't have nearly as much time for leisure reading as I'd like. If I manage to read an entire course book instead of just the assigned chapters, I'll review that here, too.
If you've read the first three Sciences of Discworld, you know the drill: A short Discworld story is interspersed by long discourses on somewhat related science. I've enjoyed all of them so far, though perhaps Darwin's Watch most of all. This time around, a little fatigue has set in. That, and Richard Dawkins is a sexist asshole and I'm not too fond of having him uncritically praised just because he happens to be the most visible face of today's atheism.
The Discworld story concerns a dispute between conservative Omnians and the wizards on the intellectual property right of Roundworld, meaning the universe which contains our own round Earth, which the wizards created in a magical accident and store in the Unseen University. It also introduces Discworld's first official Mary Sue, a librarian from England called Marjorie Daw, who is very sensible and has cosmological discussions with Archchancellor Ridcully over tea and biscuits. (That's just how Discworld WOULD do the Mary Sue trope.)
The science part roams over the shape and nature of the universe, of particle physics, embryo formation, early life forms, and various flaws in commonly accepted or widely supported assumptions about the way things work, expounding systems thinking to explain away the need for finely balanced universal constants to enable life... oh, just read it. It was fun. It also clocked a lot more word count than the story, but that's been the case with all SoDs.
I do have a bone to pick: That the saunter through the wonders of the universe is tied up with, employed in the service of, and constantly interrupted by an encomium to atheism. I'm not saying organized religion isn't a tool for power as well as a comfort for those tired of uncertainty, or that it doesn't do any damage. That's human power politics and dominant ideologies for you. It just gets boring, repetitive, and annoying, and it makes me want to go perform some religious service just to spite them. I was there for the science and for the Discworld, not for the authors' anxiety over the sanity of the human race.