If we're looking at say a crime detective novel from the 1930's, there's a lot that the writer can take for granted. Even today someone who uses the term "piece", "heater", "roscoe", you know that they're talking about a gun. We don't have that here. This is an entirely different universe where over a millenium of history has passed by and we've missed it. Personally, I'm glad he's explaining things and bringing us along as the story continues.