October's recommendation: The Difference Engine, by William Gibson and Bruce Sterling.
More research? You bet! But this time it was for a different project.
The Difference Engine is a classic of alternate-history steampunk. The breakpoint is that the computer age came a century early: Charles Babbage actually built his Analytical Engine, and now you have a Victorian England full of steam-powered computers (and steam-powered everything else, too).
That's the immediately obvious change. The others take longer to pick up on. The prime minister, Lord Byron, is that Lord Byron -- he never went off to get killed in Greece. And Keats somehow avoided dying of consumption. And Shelley may or may not be alive anymore, but that's because the characters disagree on whether he died in the secret jail Byron chucked him into. I'm not sure why Gibson and Sterling decided all the Romantic poets lived, but they did, and Byron most of all had a huge influence on English politics.
Because these are not the politics you know from your history. The Industrial Radical Party effected a takeover of English government (though the explanation of how and when comes at the very end of the book, in something that looks rather like an appendix, though it isn't labeled as such), and now the Rad Lords have abolished the old, hereditary aristocracy, replacing it with a merit -based system of lordship that particularly elevates "savants" -- which is to say scholars. (It's kind of gratifying wish-fulfillment, if you're the sort of person who despairs over the anti-intellectualism in American culture right now.)
In fact, history's kind of a fascinating mess in this book. British diplomacy ensured North American fragmentation, so that now, in 1855, you have the U.S.A., the C.S.A., the Republic of Texas, the Massachusetts Commune (founded by Karl Marx), French Mexico, British Canada, and the Republic of California. The Great Stink of London comes three years early. Japan's already had its Meiji Restoration, set off by Britain instead of the U.S. Etc. I don't quite know my nineteenth-century history well enough to spot all the changes, but I can tell there are a lot.
Of course, in all of this I have yet to say anything about the characters or plot. Sadly, that is in part because I think they're the weaker part of the novel. There are three main characters, each taken in turn: Sybil Gerard, daughter of an executed Luddite agitator; Edward Mallory, a paleontologist; and Laurience Oliphant, a spy with weird mystical leanings that never quite came clear for me. They seem a motley bunch, and they are, because in the end I think the book is more about the society Gibson and Sterling postulate, less about the people in it.
Evidence of this may be found in the macguffin that ostensibly holds the plot together. There are a few brief appearances by a box of punch-cards, a computer program that people are trying to get ahold of, which seem to have originated with Ada Byron (who never married, hence is not called Ada Lovelace). This is where the book falls apart for me: the ultimate answer as to what those cards are is both disappointing and very nearly irrelevant to the story. Mallory is the most interesting character to me, and fortunately occupies the greatest part of the novel, but he and Sybil and Oliphant don't connect very well. The end of the book falls apart into wtf? I looked to its last section for some kind of resolution, but in retrospect I think it was more of an appendix than anything else. I think it's characteristic of the type of book this really is -- it's also kind of hard SF and cyberpunk-y, in addition to the genres I already named -- and maybe the ending works for that kind of reader. For me, though, when all was said and done, what I took away was a fascinating setting, some neat events, and an interesting character or two.
But those things were cool enough that, despite my disappointment with the plot, I still think the book is worth picking up.