Historical research has contributed to our understanding of the evolution of juvenile justice and public school bureaucracies. Yet, these institutions remain an enigma as long as the rules guiding their actors cannot be identified with law, professional standards, or policy. Sociologists have used participant observation to disclose such “informal” or “backstage” understandings and rules, which are shared by organizational actors but not with the public. However, participant observation is limited, notably in its absence of historical and systemic perspectives. Because backstage rules have a history and are symbiotically related to bureaucratic evolution, a historical perspective may also contribute to unraveling this enigmatic aspect of public bureaucracies.