Book excerpt: In the latter part of the 20th century, humans are doing a particularly poor job of managing natural resources in a sustainable way over the long term. Institutions, Ecosystems and sustainability focuses on long term, sustainable natural resource management practices at the local, national, and international levels. The authors suggest that a major cause of the "sustainability problem" lie in "scale" problems. Large scale ecosystems are not simply larger versions of smaller systems, and micro-scale ecosystems are not merely microcosims of large scale systems. The driving forces and feedback mechanisms operate at different levels and exhibit distinct patterns of their own. The challenge is to match ecosystems and governance systems in ways that maximize the compatibility of these systems. This book builds upon this fundamental principle. Particularly valuable is the use of simulation exercises to explore the consequences of social institutions and a discussion of the progress being made in developing a broad global data base to test hypotheses about the relationship between ecosystems and social institutions, and to investigate ways to repair the damage already caused by scale mismatches.