"Book is missing a key component."
Crucial Conversations presumes you are engaged in a difficult conversation with a peer (spouse) or a subordinate at work. Unfortunately, many difficult conversations occur where someone in a position of power presents their argument as "silence or violence" such as your manager or a large firm with which you are engaged in negotations.
Crucial Conversations offers little to no advice on how to revert an aggresive individual to a productive manner of speaking. "Getting to Yes" is a a book that discusses negotiating from somewhere other than a position of power.
Only after you have read that book would I recommend topping up your communication skills with this book.