The book was not really what I expected, although I'm not sure what I expected. I guess I hoped for more war -- placing authorities against each other on the nitpicky rules of grammar we all love and/or hate. Instead, it was more of a history of how people have formalized the English language, from early grammars to modern linguistics. A strong undercurrent is the prescriptivist bent of 'grammarians' and the descriptivist bent of linguists.
I think I hoped for more amusing little tidbits, and although they are there, it is like one of those disappointing pours of breakfast cereal that you got as a kid, where you mourned that there weren't more dehydrated marshmallows among the cat kibble. Perhaps because it was a slower slog to get through the book, I've forgotten most of the tidbits already. One that did stick was the idea that, after the Civil War, where one side had been associated with 'the Union', the use of that phrase for the country as a whole fell out of fashion. The constitution speaks of forming a more perfect union, and a state of the union address. In the post-war period, we began to speak of the US as a nation. Perhaps related to this, around 1900 the government printing office (IIRC) made a declaration to standardize that "the United States" was a singular noun.