Operating theory: Neal Stephenson has access to a time machine where he can zap back to past centuries to observe little details that make the world described in Quicksilver (et. al.) seem so authentically rendered.
Or maybe he just reads and travels a lot.
It's big. Let me get that out of the way. 916 pages of main text. And it's not easy going, took me 32 days to get through it, and I skimmed. I was reminded of what the late great William Goldman did with S. Morganstern's novel The Princess Bride: brought out a "good parts" version, omitting all the Florinese political commentary.
I'm not sure what you could leave out of Quicksilver, though.
It begins in 1713 Massachusetts, where Enoch Root has traveled to fetch old Daniel Waterhouse from his position at the "Massachusetts Bay Colony Institute of Technologickal Arts". He needs to travel back across the Atlantic to try to mend the calculus feud between Newton and Leibniz. Pirates interfere.
Most of the book is set decades earlier. In addition to Daniel's story, we're also introduced to Jack Shaftoe. Jack starts out as a London street rat, but graduates to the life of vagabond and mercenary. While looting a war-torn Vienna, he rescues fair Eliza (a native of the fictional but picturesque isle of Qwghlm) from a Turkish harem. That's a meet-cute, isn't it? Ah, but true love never runs smooth, as Eliza eventually gets pissed enough at Jack to fling a harpoon at him.
Well, piles of stuff happens. And this is only the first book of three.
If you've read Cryptonomicon, you'll recognize Jack and Daniel as the ancestors of the 20th-century characters there. (You'll also recognize Enoch Root, who appears to be somewhat immortal.)
The book is also set against actual historical events: the Great Plague, the London Fire, the Glorious Revolution, and more. And actual historical figures, too. In addition to Newton and Leibniz: Locke, Pepys, Hooke, Bacon, Boyle,… And a lot of royalty and nobility.