Flash vs Flex vs AIR

Moock keeps mentioning Adobe AIR in Chapter 27 and how it has CSS & js capabilities. Does that mean that AIR is better than Flash? Am I studying something that's going to die in a couple of years!? Why don't I know anything... the only thing I know about AIR is that TweetDeck uses it right? And it crashed my browser when I tried to install it.

and this post comparing Flash & AIR is from 2007:
http://www.scottklarr.com/topic/39/adobe-air-vs-flash-vs-flex-vs-microso...

too much catch-up! i'm thinking of becoming a nutritionist instead.