My copy is rather outdated. It lauds historical figures that have since been revealed to be anywhere from flawed to profoundly corrupt, although their status as heroes grants them some immunity from exposure depending on the nature of their sins. That aside, it's really just a big book of tips. They're useful tips but you've probably heard them all before. You could probably get through a public speaking course without this book, honestly, because it's practicing that's the hard part.
I have this book because the university bookstore would only give me 75 cents for it, so there it sits, a good reference book for the distant future when I teach my children about public speaking.