Books.Google.com/books, will often have extensive previews of books. There are sometimes previews of additional sections of the book in question, too, found here and there on the Internet, but it's a pain to look for them.
Those who are interested in politics would come up with their own two numbers, if asked. Of course, conservatives would tend to have their answers skewed one direction, and liberals would tend to have their results skewed in another direction.
Would anyone be interested in knowing all of the
possible (meaning chosen
at random) combinations of the 13 presidents? It's 169. You arrive at that number by multiplying 13 times 13.
I bought the ebook. I have very, very little interest in politics anymore (I was a political
activist in college!). I looked at the book as having 13 biographies of presidents for 99 cents--a book to skim through for nuggets, while ignoring the political stuff.