This book comprises eighteen wide-ranging essays that share a common theme: the centrality of joint commitment to human life, both private and public. After an opening chapter that introduces joint commitment and the themes of the book, It is divided into four sections: shared agency; collective attitudes; mutual recognition, promises, and love; and political life. An important aspect of joint commitment is its provision of directed obligations and rights to the parties. These obligations are to be distinguished from moral requirements with or without special features. Another significant aspect of of joint commitment is that it can plausibly be said to unify the parties. In addition, it binds or obligates them to one another in a particularly intransigeant way: no one party is in a position unilaterally to rescind the joint commitment. Invoking one or more of these features of joint commitment, Margaret Gilbert offers reasoned accounts of a variety of phenomena both small and large in scale-from the mutual recognition of two people to patriotism, from marital love to political obligation. Overall the essays in this book continue the development of the plural subject theory for which Gilbert is now famous, both refining or amplifying her earlier accounts of important social phenomena such as social conventions, and offering new applications of her theory, as in her account of shared values, and her discussion of the unity of the European Union.