In the years following her role as the lead author of the international bestseller, Limits to Growth, Donella Meadows remained a pioneer of environmental and social analysis until her untimely death in 2001. Meadows’ newly released manuscript, edited by the Sustainability Institute’s Diana Wright, brings systems thinking out of the realm of computers and equations and into the tangible world, showing readers how to develop the systems-thinking skills that thought leaders across the globe consider critical for 21st-century life. Some of the biggest problems facing the world – war, hunger, poverty, and environmental degradation – are essentially system failures. They cannot be solved by fixing one piece in isolation from the others, because even seemingly minor details have enormous power to undermine the best efforts of too-narrow thinking. Although both tools and methods are included, the heart of the book reminds readers to pay attention to what is important, not just what is quantifiable, to stay humble and to continue to learn. Thinking in Systems helps readers avoid confusion and helplessness, the first step toward finding proactive and effective solutions.