Can theory be important in a field as applied, practical, and interdisciplinary as public administration? This book answers this question with another firm yes. We believe it is self-evident that a need exists for greater conceptual clarity and theoretical reliability in our treatment of public administration. It is always tempting in an applied field to fall back on common sense and wisdom as sufficient to the task of implementing public policy. In fact, common sense and wisdom are necessary for carrying out effective policy, but they are not sufficient, especially when common sense and wisdom are poorly defined or not defined at all. Deep thinking is also helpful, but insufficient. The certainties derived from the deep thought of one generation are often poor guides for succeeding generations. For example, it is presently accepted almost universally that public bureaucracies are slow, cumbersome, self-serving, and inefficient—the common sense or wisdom of our day. We act on that common sense by deregulating, downsizing, contracting-out, privatizing, encouraging bureaucratic risk taking and innovation, and loosening controls on government purchasing and bidding. Sixty years ago, when the United State was in a deep economic depression, an opposite type of common sense prevailed. Based on that common sense now rapidly moving away from dependence on centralized government, and common sense and conventional wisdom appear to guide these trends.