This article focuses on the question, how have the theoretical and substantive concerns of the public administration community changed over time? in other words: What is mainstream public administration and how has it changed? To answer this question, we analyzed the contents of a sample of over 50 years of PAR articles. The Classification Scheme Content analysis presupposes the existence of a scheme of content categories for use in text classification. The task of distinguishing the appropriate category for a particular PAR article required identification of the salient attributes of that article and matching these attributes with the characteristic attributes of one of the content categories. Articles in the same category were presumed to have similar identifiable attributes. The idea behind this approach was to use established empirical methods to answer the research question by drawing inferences from the frequency with which PAR articles appeared in the various categories. The frequencies of articles in categories were presumed to reflect the relative emphasis placed by public administrators and academics on the corresponding activity areas. Likewise, changes in these frequencies over time were presumed to reflect corresponding changes in emphasis in the field. In addition, different people must classify the same article in the same way. It turned out that the pertinent categories presented themselves with notable clarity through examination of consistencies across introductory public administration textbooks; a more-or-less common classification scheme was used by textbook authors. Such categories offered a highly respectable approximation to administrative activity. Thus an article about public finance could be readily categorized differently, for example, from an article about human resources management or organizational theory. The introductory textbooks upon which the category scheme was based included Denhardt (1991), Henry (1989), Palumbo and Maynard-Moody (1991), Rosenbloom (1988), and Straussman (1990). Through a review of these texts, we clustered public administration interest and activity into 14 distinct categories. Table 1 presents abbreviated definitions of the topical categories derived from the texts reviewed. [TABULAR DATA 1 OMITTED] Expectations It was hypothesized that the emphasis given to the various categories in PAR would shift over the years. For example, we expected that the percentage of articles devoted to the category intergovernmental relations would be fairly limited during the 1940s and 1950s but would then blossom during the 1960s as intergovernmental programs expanded under the administration of Lyndon Johnson. Interest in intergovernmental relations was then expected to remain fairly high during the 1970s as block grants and revenue sharing appeared and as scholars wrote of an overloaded and ineffective system. Concern was expected to remain at a fairly high level during the early 1980s as debate about President Reagan's attempted devolution of federal programs to the states occurred. A different pattern might be expected concerning the number of articles dealing primarily with ethics in public administration. A concern with ethical issues in government might be viewed as a fairly recent phenomenon--reaching back to about the Watergate era. From an academic perspective, however, a significant concern with ethical issues in public administration is probably even more recent--a characteristic of the 1980s. The two categories, implementation and program evaluation/planning, were expected to exhibit similar patterns of interest. Interest in implementation essentially dates back only to Pressman and Wildavsky's book, Implementation (1973). The concern that they, and others, raised--that many government programs do not work--led legislative bodies and grantors to require that planning and evaluation be an integral part of most programs. …