Bad, but in a good way-

There's few pleasures as bracing as a joyously bad review:

It is a great gift to the reviewer when a book’s author all but admits in the introduction that his whole project is horseshit. 

Props, then, to Allan Metcalf, whose Introduction introduces some caveats; and who then includes a subsection called “Some Caveats” introducing some more. 

You can see why this was called for. The gimmick for this fun-sized contribution to the pop-etymology shelves is that it selects and glosses a handful of representative words for each generation...