What is the outcome of Guns, Germs, and Steel?

It is a
little bit difficult to say that has an outcome.  A non- book is not
typically said to have an outcome.  As it is, I suppose we could say that the outcome of this
book is that Diamond says that he has proved his thesis.  Of course, it would be a huge surprise
if he did not prove it.

So, we can say that the outcome is that Diamond
proves that...