Patton's Spaceship (1997) 320 pages by John Barnes.

This book starts in what could be our Earth. This Earth is in a timeline that is just one of millions. Some timelines are very similar, some are vastly different. The timeline of the Closers was the first to discover how to move between them and are intent on turning events in a particular direction, totalitarian society, which they can then take over.

Mark Strang is a professional bodyguard whose father investigates and writes about terrorist organizations. Mark quickly gets involved in trying to protect our timeline from these terrorists. A fluke lands him in another timeline. This one is a 1960s world where Hitler won WWII.

Mark is stranded there, and being stranded, has to try his best to turn that world into something better.

There was a lot of action, the first chapter fight scene seemed to be described in minute detail. I thought Barnes did a good job of fleshing out his characters, at least that of Mark. It did seem quite straightforward good vs. evil. Not much in between. There was one glaring error, where he said Hydrogen gave four times the lift of Helium. It's closer to (28-1)/(28-4), it's the displaced N2, O2 and H2O that provide lift for a blimp or dirigible.

I enjoyed it. The book was good enough that the next book that I'm reading is the second timeline wars novel.