Especially, I learned why we put transitions and exposition in books--because Brasyl doesn't have that stuff.
Don't get me wrong; it's a brilliant book and a seriously amazing achievement, but I'm a pretty hip and attentive reader, and I know I lost a ton of what was going on in the sheer tightness and density of the book's concentrated information delivery. There was no room to catch your breath.
As You Know, Bob, I'm a big proponent of getting every word in a story to do as much work as possible--I think every sentence should build or resolve tension, woldbuild, develop character, develop theme, and advance the plot (pick at least two)--but one thing I'm starting to realize is that sometimes, letting air into a story is a kind of work, also.
I also joke about not worrying too much about readers who don't want to do a little work. "You must be as tall as this sign to ride this ride."
Well, my experience with Brasyl was very close to "You must be as tall as this sign to attack this city." Heluva book; I could only read it four pages at a time, and I kept losing the threads of what was going on.
Because the jump-cut ethos of the book means that it takes effort with each scene break to orient youself (which is an artistic choice in this case; this is an observation rather than a critique), which messes with the line of direction and the flow through the book, and results in a somewhat mentally strenuous reading process. (Probably not unlike the sense of disorientation a number of readers have complained about with Blood & Iron, which (among all its other qualities) is my novel-length attempt to actually demonstrate the way my weird nonlinear kinesthetic brain functions on paper.)
So yeah, I've learned a lot. I've learned some things about why we exposit and why we write transitions, and how we can do both unobtrusively, and why we provide a little guidance--line of direction, the camera track and points of focus through the long shot (to strain a metaphor)--for the reader as he comes along with us. Some of it's direction, and some of it's misdirection, and all of it's important. And it's important when you chose not to use it, either, to abandon those guides and assists and kick the reader in neck-deep and see if she can swim.