This primer traces the roots of the climate crisis as well as other social crises to the dominant economic paradigm and the prevailing socio-economic system in the world today -- a system that has proven capable of generating unprecedented wealth for some at the same time impoverishing the majority of the people and devastating the planet. It shows the limits and adverse implications of profit-oriented technological fixes and market-based solutions being promoted by corporate and elite interests who are determined to maintain the status quo.  It points to the need for a radical change in the distribution of wealth and power within societies and between countries in order to arrest climate change and shift towards sustainable human development.  The primer concludes by identifying urgent tasks for social movements fighting for a just and sustainable future.