The book by Williamson, that I have and described, is a trade paperback.
I love history; just not all of it. This is just one of the eras/subjects that I'm crazy about, so I've read lots of books about it, both fiction and nonfiction.
(That's part of the reason for all the debate over the Wars of the Roses and Richard III.)
Here's the cover I remember, library edition in the local Cobb County library: