A Book on Emotions

I'm at the moment working on translating a book on the psychology of emotions. What I've covered so far has been quite informative. Did you know that our experience of emotions manifests itself in physiological changes? If we are happy, sad, angry, anxious, frightened etc, we'll find a change in our heart-beat rates, breathing rates, sweating, etc. But there is also a reversed correlation: influencing our facial expressions and body-posture can affect some of the emotions we experience.
Makes you wonder, doesn't it?