Chances are you've heard of Mark Twain's A Connecticut Yankee in King Arthur's Court and maybe have read it. Almost certainly you've seen some variation of it on TV at one time or another. Most such variations are pretty unimaginative, barely doing anything more than Twain had already done, if even that much.
Over a year ago I saw a mention of 1632 by Eric Flint, and bought it as it was a variation that sounded truly interesting. Instead of only one person or even a tiny party of time travelers, an entire town gets thrown across time and space. A small town, but still a whole town. It's the small town of Grantville, West Virginia, and around April 2000 something happens. This something transports the town to Germany in the 1630s, where the 30 Years War is going on. It takes a while for folks to work out just what happened (or rather, just what was the result of whatever happened) and then decide how to deal with it all. Returning to West Virginia in 2000 is out because they simply don't know how.
This has become a series of books, dealing with succeeding years and various events of those years. There are at least three books just for 1634 as that much is going on. As Eric Flint says, "History is messy" and it's not all cut and dried as many history texts might indicate. There are other books, the Grantville Gazettes and a couple others that are collections of shorter stories by other authors, filling in background on some characters and events.
I have not read all of the books, but I have read a number of them. They are interesting not only for the story itself, but for revealing some historical characters. Before I started reading these, Oliver Cromwell and Cardinal Richelieu, as just two examples, were just names of historical characters but I really didn't know anything about them. Also there is the matter of how to do things with 1630s technology. Even with 2000 know-how (and not all of that made the trip - Grantville is a small town, and not a major industrial or research center) there is the matter of materials. It's going to be a while before there's any significant amount of new aluminum, stainless steel, or plastics. The Gazettes are not all fiction. There are separate articles on various aspects, ranging from the problem of getting good draft horses to what it would take to make telecommunications work at just 19th century levels.
I've just finished reading 1635: Cannon Law (that's not a typo) and found it good except that it feels like it just ended and it should have been marked 'Part One'. I expect there will be a book along eventually that picks up where this one leaves off, but I don't know when I'll get to it.
That aside, I really like the series. Eric Flint said he had two objectives in writing 1632 beyond just making a good book. One was that the story would not make out small town or rural inhabitants as idiots. Real people, with their flaws, yes. But not fools who don't know any better than to do foolish things. That includes the people of the 1630s as well, not just the transplants from Grantville. Yes, there are some fools, but everybody around them recognizes that. The other was that it would not be yet another depressing dystopian story. There would be hope for the future, though it would not be easy and would experience setbacks, the general mood is that people can and will overcome problems and overall things will improve. I like both of these objectives and I think the 1632 series succeeds in meeting them.