Even with this reconciliation, theory-building in public administration is in fluenced by tastes and fashions. There is always the law of the instrument: When the theorist has a methodological or conceptual hammer, everything begins to look like a nail. In the policy schools, the case method has taken some aspects of a hammer; the market model and mathematical conclusions so derived have been applied to a lot of nails lately. NeFrom the traditionalist and behaviorist positions of thirty years ago, public administration has evolved to a field enjoying a considerable theoretical richness. A single dominant theory, an intellectual hegemony, would have impoverished the field, instead, there are several strong and important theories and many important theorists, a condition befitting a field as applied and interdisciplinary as public administration.vertheless, despite examples of methodological and theoretical excesses, public administration theory has never been healthier than at present.