Try your local book store---Barnes and Noble, Waldonbooks, B. Dalton, etc. I know Ballentine Paperbacks had a book out about his entire military career, not quite a full biography. I bought a copy of it way back when I was in High School in the late 70's. If it isn't still in print, their computer system should be able to get you a title to look for at a second hand bookseller.