Our human lives involve remarkable forms of practical organization— diachronic organization of individual activity; small-scale organization of shared action; and the organization of institutions. In this book, Michael Bratman argues that the key to these multiple, inter-related forms of human practical organization is our capacity for planning agency. Drawing on earlier work on the roles of planning agency in our human, cross-temporal and small-scale social organization, it focuses on the role of planning agency within our organized institutions, whether a religious congregation, a small business, a professional association, a city council, a university, a non-profit organization, a corporation, a political party, a legal system, or a democratic state. Shared and Institutional Agency draws on ideas, inspired by H.L.A. Hart, that our organized institutions are rule-guided, and that to understand this, we need a theory of social rules. This book develops a planning theory of social rules and puts forth an organized institution as involving authority-according social rules of procedure. This supports a model of organized institutions that makes room for pluralistic divergence and leads to a model of institutional intention and institutional intentional agency. The view that emerges sees our capacity for planning agency as a core capacity that underlies not only string quartets and informal social rules, but also the rule-guided structure of organized institutions and institutional agency.