The Fiction Factory By John Milton Edwards, Being the Experience of a Writer who, for Twenty-two Years, has kept a Story-mill Grinding Successfully, William Wallace Cook, 1912
The Google Books version is the one I read because it was easiest. There are several fascinating chapters in that book, and the rest is at the very least interesting. I haven’t quite finished the book, but I’m very close. Give it a shot if you enjoy reading about writers’ lives or processes.