Sparring with Hemingway was a book that included bouts with the undisputed champion of what weight class from 1980 to 1987?
Marvelous Marvin Hagler:  He reigned as the undisputed middleweight champion from 1980 to 1987, making twelve defenses of that title, and currently holds the highest knockout percentage of all undisputed middleweight champions, at 78%.
i don't know