Economists and political observers in recent years have bemoaned the decline of American competitiveness in traditional industries such as steel, automobiles, and textiles. Some of these observers worry that the U.S. economy will increasingly be dominated by service industries. At least one service industry in the United States does appear to be growing and thriving, despite some very adverse economic circumstances. That industry is the non-profit public policy research industry, more commonly known as “think tanks.” The think tank universe has become much more diverse over the past decade, reflecting both new entrants into the marketplace of ideas and changes in these organizations' environment. There are, moreover, inherent tensions in any of the three main models (“university without students,” contract researcher, and advocacy tank) that think tanks may pursue. Attempting to mix the models can be difficult too.These tensions and environmental changes have created tremendous uncertainty, but also some entrepreneurial opportunities, for think tank managers. Increasingly, these managers must be concerned with finding a viable niche in a crowded, fragmented market. And they must do so while dealing with staffs who may be resistant not only to specific courses of change, but also to external direction of any sort.