Please don't read this post if you don't want to hear about the plot of Avatar.
I had just read The Wayfinders: Why Ancient Wisdom Matters in the Modern World (Wade Davis, 2009) when I went to see Avatar. The movie is sensational entertainment: it is also a vehicle for James Cameron's environmental message. The book is heavier going - it discusses human cultures and the ethnosphere - it reminds us that " the path that we (the developed world) have taken is not the only one available .... by their very existence, the diverse cultures of the world bear witness " to different ways of living.