The Secret Life of Words
The Secret Life of Words: How English Became English
Author: Henry Hitchings
Amazon info
Even for an admitted word geek, this was a big too much like reading a dictionary, although the material is organized historically which provides a basic framework for the book. I found it too easy to lose sight of the big picture in the details of the derivations of particular words.
The other obvious point is that this is a history of English, not of American, so it tells the story from the perspective of someone who is quite familiar with English history - which means that at least some references were lost on me.
Perhaps I would get more out of it on a second read or perhaps there are better options.
Recommended: Only for true word geeks.