It's a blog! Mainly of book reviews.
In one sense this is the most ambitious SF novel I've ever read. In every other it's kinda insipid. That one sense? The science! Generally, SF that isn't actually Engineering Fiction or (the very rare) Mathematics Fiction or Alternative History does its science by saying those scientific laws you know? They're approximately right but what if there was this extra thing I've made up? (Hyperspace, wormholes that don't have singularities in the middle, infinite computing power...)
Egan asks, what if the fundamental topology, geometry and laws of relativity were in fact different? (Here's a universe where there's no maximum velocity, time behaves exactly like space, in terms of laws of motion, oh, and the universe is the shape of a ring doughnut.) The answer is, apparently, then your story is 50% exposition about the consequences for physics, chemistry and biology, as discovered by our characters. Said consequences are very weird indeed and require more graphs than I've ever seen in a novel before, by some stretch. Perhaps the most weird thing, though, is that the consequences for alien psychology and social structure are almost negligable...
I'm pretty excited about reading the two follow-up volumes but mainly because I want to know how microscopic physics works over there in Torus Universe. Whether and how the aliens save their planet come a long distant second and third. How this stuff is supposed to appeal to anybody without a physics BSc, I don't know.