H.(enry) Beam Piper was an American science fiction writer who died in 1964(there seems to be some disagreement as one source has a different date). His most well known books were likely the Fuzzy novels, but the Paratime stories aren’t far behind.
They are alternate universe tales about one time line that has the secret of crossing into other lines and jealously guard that secret. They plunder those other lines for their natural resources to prop up their own depleted one. The Paratime Police keep the secret and “police” abuses, appearing in a series of short stories collected in Paratime and there was one novel, the subject of this post. Published in 1965, it’s an expansion of a fifties novelette, GUNPOWDER GOD.
Corporal Calvin Morrison is a Pennsylvania state trooper chasing down a felon who gets caught up in one of the conveyors and ends up in an alternate reality Pennsylvania much more primitive. In this reality, the North American continent had been colonized by nomads across the land bridge from Asia into Alaska.
No large cities, a lot of forest, speaking a language he doesn’t recognize, using flintlock pistols, Calvin initially helps a group of peasants fight off raiders with his police revolver. Wounded by a young woman leading the raiders, he recovers and learns the language while doing so, also learning a little of the history of his new world.
North America is split into kingdoms about late renaissance period and he’s the guest of the principality of Hostigos. Two of it neighbor kingdoms threaten it and a third stands by looking to pick up the pieces from the coming battle. You see, the priests of the god Styphon want Hostigos destroyed. The sect controls the secret of fireseed(gunpowder) and Hostigos has sulpher springs they covet.
Calvin, Lord Kalvin as he becomes known in the kingdom, knows the formula for gunpowder and gets production started to combat the various powers that want to divide Hostigos. His knowledge of military tactics help the small, outnumbered army defeat their enemies. He also spreads the secret of fireseed far and wide to stymie the Styphon priests.
Kalvan’s power increases as the people look to him and he begins the process of uniting the different kingdoms under one rule, reluctantly assuming rule as his popularity grows.
The Paratime Police are not happy, fearing Kalvan might reveal the alternate reality secret. They send someone to grab him.
A sequel by Roland Green and John F. Carr, GREAT KINGS’ WAR, was authorized and picks up the story. There are other sequels by Carr that continue the story of the displaced state trooper though I haven’t read those. By a small publisher, they are kind of pricey.
A good tale.
Not The Baseball Pitcher 
I liked the Kalvan books quite a bit. I didn’t know about the sequels by Carr and others though. I’ll have to check those out. The idea was interesting enough.
I don’t know whether the title or his name is more interesting.
Check Frederik Pohl’s blog for a short but telling memoir of Piper.
http://www.thewaythefutureblogs.com/2010/01/h-beam-piper/
You know, Patti, I’ve been aware of Piper so long that I had to think about the risibility of the form he preferred of his name.
Dang. I remember this one. And had, of course, forgotten it. Good stuff.