For speakers who need to communicate effectively to people whether for life purpose or just to sound great in personal life (both my case), I wholeheartedly recommend this book. I've been reading it and doing some daily exercises it has for about a month. It has revealed both the flaws and potential of my own voice and the tools to tweak it. I'm writing this after a big breakthrough for me, to the point where I'm actually certain that if I keep going, I'll be able to record and deliver my message in a voice people will want to listen to. Yes, how you sound matters immensely if you're trying to influence people. And you can train it. It's not something we're stuck with. Tip: Make sure you don't base anything upon how you feel or sound to yourself when you speak. Only rely on recordings of yourself. I got stuck in an illusion that I was sounding great for a while but then listening to my recording shattered it (got a little depressed, but then I managed to fix the problem).