How does the rest of the book read in terms of believability?
Horrible.
Oliva does himself absolutely no favors.
He contradicts so many things he has said in the past, as though he has forgotten many truths.
He calls racism, for instance, when Arnold beats him in the 70 O, when Oliva had won the past three and beaten white guys.
Terribly written, grammar is horrible.
Wish I could say something positive, but he is VERY disingenuous in this 'book'.