Books that are worthwhile-

1) The relaxation response.
Talks about "the relaxation response" (durrrr). Natures antidote to the fight, flight, or freeze response.

2) Real Happiness
Amazing "how to" book on meditation. I honestly think if you want to get good at being chill under stress you need consistent meditation.

3) Mindfulness in plain english.
Great for explaining these types of concepts to the western mind.

4) Flow
A book about the state we are all searching for.