The First Book from Medicine Wagon, a Supernatural Western series, 1880s. Kind of like Remo and Chiun meet Tex Arcana vs Jonah Hex

This guy crossed over, was revived by lightning and came back. He's got a page from an archaic occult script in his boot. That's why he crossed over and came back. Supernatural power.

He encounters a guy who's "the medicine man" in my mind, a snake oil guy with a gypsy wagon.  

Medicine Man is looking for these pages and sections from a Necronomicon type Tome. 

Now he's got Lynch to find them for him.  

Other guys are looking too. Wizards, gunslingers. Preachers with secrets. Doomed Civil War Raiders. 

Wherever the adventure leads in each paperback, it's gunfights, darkness and people after these pages to assemble the Tome. 

 Something about the document that saved his life. 

My feeling is not that the old man planted it, but that Lynch and the document found each other. 

The old man isn't exactly a wizard, more of a scholar. He needs Lynch to do the work. Like a Sackett or Hondo, he has his own side quests. 

But... People, things that look like people, Medicine Man, some mysterious beautiful widow from Lynch's past.

They're in a rush, trying to assemble a Tome, from fragments, pages, sections  recipes, drawings, maps of... Not places, exactly. And the actual binder for it.