The challenges of Peak Oil and Climate Change are the primary drivers of the Transition movement, of its sense of urgency. Over time however it has become clear that the process of addressing them will involve broad and deep changes to every aspect of our society and that work in many other areas will be a critical part of the process.
If you wish to explore these related issues including economics, health, education and more, the Post Carbon Institute has introductory material on each here: http://www.postcarbon.org/issues
A word of caution is that overwhelm is one of our challenges and the above link represents is an extensive program of study. A word of recommendation is that the transition movement includes enough subject areas that anyone can find a place within it where they can connect, contribute and express their values and passion.