I tend to refer my coaching clients to "Fierce Conversations" when they are having trouble getting motivated and avoid a lot of uncomfortable conversations (compared to recommending other books for those who botch difficult conversations).
Susan's section on "stump speeches" is good for gaining clarity on personal vision (i.e., where are you going, why, who is going with you, and how will you get there?).
Once clear on "where you are going," it's time to start noticing and speaking about what "you're pretending not to know" (otherwise known as breakdowns -- yours or others).
Although "Fierce Conversations" doesn't cover the underlying emotions like "Difficult Conversations" or "Nonviolent Communications" do, or the styles under stress (silence or violence) as "Crucial Conversations" does, it does have some good discussion on "interrogating reality" (with an emphasis on questions and remaining curious) and identifying your own role in conversational breakdowns.
Fierce, difficult, crucial, nonviolent -- whatever you call these conversations, they're at the core of all meaningful relationships. I can definitely recommend "Fierce Conversations" to the mix of books on skillful conversations.