Guns o' the South
I read the first couple of books in Harry Turtledove's series called Worldwar. A storyline in which aliens invade the planet in the middle of World War II. After a couple of books the story became a little monotonous for me but for a while there I was really enjoying it.
Right now I am reading his book, Guns of the South. In a nutshell, a group of white supremacists from the future show up with AK-47's, MRE's and hand grenades and help the South win the civil war. Armed with AK-47's Confederacy ends the war pretty quickly. In fact, General Lee actually captures Washington City, as it's called. I think he may have wrote this book just so he could write the dialog between Lee and Lincoln that takes place in the White House. It's an exchange between to towering figures from history that comes off as some of the most genuine feeling historical fiction writing I have ever read. It's quite a feat to take a story with such a fantastic premise and insert such realistic dialog. I was quite taken aback.
This happens barely halfway through the book and now the negotiations between the two former warring nations are starting. I am digging this book.
After I got tired of the Worldwar series I wrote Turtledove off a little bit. What has convinced me to delve in Guns of the South is the collection of short stories by Turtledove that I bought a few months ago. I was really impressed by a story about the apocalypse taking place in the middle of trench warfare during World War I. None of the soldiers noticed.