The traditional focus in adminstrative law on agency discretion prevents us from appreciating the extent of private participation in governance. Although legal scholars have long acknowledged some forms of private engagement with public agencies, such as lobbying and litigation, non-government actors remain marginal in a field dominated by agency action. Private actors are involved in myriad ways in every dimension of the regulatory and administrative process. Their role in governance has taken on even greater importance in the face of widespread privatization and contracting out, as they increasingly perform what are thought to be "public functions." The article provides illustrations of the private role in governance, arguing that the regulatory and adminstrative process is characterized by public-private interdependence. It offers a conceptualization of governance as a product of regulatory regimes in which responsibility is shared, rather than distinctly separate "public" and "private" actors. While administrative law must now orient itself to respond to private activity, scholars ought to resist the impulse to simply constrain private actors as if they were agencies, either by considering them to be "public" actors for constitutional purposes or by incorporating public law norms into private law. A deeper understanding of the private role in governance will help clarify the dangers posed by different regulatory regimes and the mechanisms -- traditional and non-traditional, formal and informal -- with which administrative law might respond. Viewing governance as a shared enterprise allows us to separate the mechanisms that produce public law values (accountability, rationality, neutrality) from the public or private nature of the decision maker. This in turn helps to cast private parties in a more realistic and balanced light. Private actors are not just rational, self-interested rent-seekers that exacerbate the traditional accountability problem in administrative law; they are also regulatory resources capable of contributing to the efficacy and legitimacy of administration.