From the introduction:
Welcome to the wonderful, dangerous, and beautiful alien world of Pandora. This lush and fertile moon is home to many exotic creatures, as well as a tribal species know as the Na'vi. Humanity has discovered that this world is rich in valuable minerals, and has set up a massive mining operation to support the failing economy of Earth. Relations between Humans and Na'vi are uneasy, and things will only get worse in the future. You arrive in 2144 and you'll be here for the next ten years, If you survive. Good luck, and remember, the air's poisonous, the planet is sentient, and Humanity has completely destroyed Earth.