A culture-bearing book, like a mule, bears the culture on its back. No one should sit down to write one deliberately. Culture-bearing books appear almost accidentally, like a sudden surge in the stock market. There are books of high quality that are a part of the culture, but that is not the same. They are a part of it. They aren't carrying it anywhere. They may talk about insanity sympathetically, for example, because that's the standard cultural attitude. But they don't carry any suggestion that insanity might be something other than sickness or degeneracy.