"Places Mentioned in this Book" Now In Some Google Book Search Results

Google has announced a new feature in the “About the Book” pages on Google Book Search. It’s called “Places Mentioned in this Book” and it displays an interactive map with pointers to cities and addresses mentioned in the text of the book.
From a Google Libraries Group message:

Readers can click and drag or zoom in/out on the map, as well as view the page numbers and snippets of text where the locations appear in the book.
For a few examples of the “places mentioned in this book” section in action, check out War and Peace or The 9/11 Commission Report.

I did a search for a few other titles and inclusion was more miss than hit. One of my favorite books, Gone with the Wind, did include the map though. This is really neat. I’ve often read books where place names were central to the story. Having a map would be helpful. Although, frankly, I doubt that I’d bother to look up from the pages of a good novel to do a Google Book Search to see the map.
It would be neat if you could search by place name in the Advanced Book Search, but, alas, you can’t. Maybe that feature will eventually be added.