In this introduction to the Policy Study Journal's special issue on punctuated equilibrium, we provide an overview of the approach, how it evolved, some of the major critiques directed at it, and some of the major developments it has spawned. We argue that the most important aspect of a theory or framework is not whether it is right or wrong, but the extent to which it is fruitful; that is, the extent to which it stimulated further research. Finally, we review the articles in this issue and put them in context.