This article discusses the ‘first generation’ of research on the core rationale underlying the delegation choice confronting legislatures vis-à-vis executive discretion. It also describes some of the major theoretical and empirical developments of a ‘second generation’ of research in the legislative delegation literature. It shows how a broadening of the conceptualization of the transaction costs of delegation has advanced theory building on the delegation of authority to American bureaucracy. In addition, four recommendations regarding how the literature on delegation studies can most fruitfully develop from a social scientific study of bureaucracy perspective are presented. These are strengthening the presumed ‘weak’ view of executive authority, providing a richer portrait of hierarchical relations within the executive branch between presidents and administrative agencies, better characterizing the ‘demand side’ of executive discretion, and discerning whether or not, and why, delegation makes a policy difference.