If you like words and writing, then go read Jack Lynch's The Lexicographer's Dilemma: The Evolution of "Proper" English, from Shakespeare to South Park. It is a history of the power of words and how people have struggled to control them. He emphasizes that the book is descriptive rather than prescriptive, and in fact some of the best parts are his descriptions of others' prescriptions. There is no ruler across the knuckles here.
Lynch documents the many unsuccessful efforts to codify and control the English language. Jonathan Swift wanted an academy (as exist for French, Spanish, and Italian) to control the entrance of new words. These days, fortunately we still have no rigid and elitist academy, but Merriam-Webster's Dictionary gets plenty of media attention for its decisions. In 2011, for example, new words included tweet, cougar, and robocall. Words also get removed, like snollygoster. We may get sick of new words, like sexting, but language is far beyond anyone's control so these new words go in regardless of whether they think they're unworthy:
English has been growing and changing haphazardly for fifteen hundred years and has never taken kindly to attempts at regulation (p. 70).
He gives countless examples of how language develops because of custom, yet people get very up in arms when someone breaks the rules. That includes me, since I cringe when I read student papers confusing its and it's, or there/they're/their. Read aloud they are the exact same, but they hurt my eyes. I care because it's wrong, yet being "wrong" just means that lots of people think it's wrong.
And thinking of wrong and right, who knew how much fighting there has been over what to include in the dictionary, with new dictionaries written to counteract the evils of other dictionaries? Etymology can be so odd--some words are so offensive that people have been wary of them for centuries yet we don't even know for sure where they originated or why. At the same time, some words are controversial now, yet in a generation or two we will forget there was a dispute (did you know that "finalize" was roundly denounced as indicative of English's decline back in the early 1960s?).
Of course, no discussion of word regulation can exclude George Carlin, whose stand-up routine on the seven words you can't say on television took on a life of its own as the FCC paid attention. (For something a bit less raunchy, his take on the language of football versus baseball is classic). The entire chapter on obscenities alone is worth it--both illuminating and funny.
I've reviewed other books about words in the past. I am a sucker for these things.