IntroductionPerhaps no movement or school of thought had more effect upon the field of American public administration in the mid-twentieth century than did logical positivism. In the late 1930s the field was beginning to flower both as a profession and as an academic discipline-due in large part to the pioneering work of classical period writers such as Frank Goodnow, Leonard White, W.F. Willoughby, Luther Gulick and Lyndall Urwick. At that time, the seeds of the logical positivist perspective were planted, mainly in the form of works published by Chester I. Barnard. He questioned the basic tenets propounded by Gulick and Urwick and, by implication, the writings of the field's first serious scholar, Woodrow Wilson. Soon the attacks were further refined and were led most notably and articulately by a young University of Chicago doctoral student named Herbert A. Simon. During the late 1940s and early 1950s, these attacks would be responsible for such a fundamental shift in the focus and composition of the discipline that, for a time, even the name "Public Administration" seemed to disappear from the academic and professional landscape. Although over 50 years and millions of critiquing words have passed since the start of the logical positivist revolution, its after effects-like lingering radiation from an atomic bomb-resonate in the discipline today as the twenty-first century dawns. This article will explore the rise of the logical positivist perspective in American public administration, its heyday, and finally its diminution. The logical positivist perspective limited, inappropriately, the scope of inquiry within the field since its adoption as the de facto epistemological perspective in the early 1950s [1]. In recent years this limitation was challenged by a call for the return to value-based traditions present in the field prior to the 1950s. Aiding in this call for a return to a values-centered approach to research in public administration has been the acceptance of alternative non-positivist methodological perspectives. Several of these perspectives, and their corresponding epistemological bases, will be discussed here.