This project investigates the complex and changing relationships between non-profit, governmental, and private business organizations as they variously cooperate or conflict with regard to energy efficiency policies and activities. Since the 1970?s energy crisis, organizations from all three of these sectors have worked to increase energy efficiency, often in very different ways. Conflicts about how energy efficiency should be defined and promoted sometimes have often led to combative actions like lawsuits. However, some organizations have also overcome their differences to collaborate in defining and promoting energy efficiency. This study will examine how relationships between nonprofit, government and business organizations have changed over time and the factors that influence these changes. The researchers will pay special attention to non-profits as a new set of forces affecting the interactions between business and government. Data from 1973 to the present on both combative and cooperative interactions around energy efficiency will give us an overall picture of how interactions have evolved. Social networks analyses will be conducted and six intensive case studies will examine the factors involved in nonprofit organizational decision making. New cooperative approaches between business, government, and the non-profit sector are key to meeting a number of complex challenges that currently face society. In addition to generating insights about effective and ineffective relationships in the energy sector, results from this study should provide some insights into how to enhance collaborative interaction around important policy issues generallly.