As Gilbert sees it, joint commitments are centrally constitutive of collective actions and attitudes, the practice of promising, conventions, political obligations and so on as per the above set of chapter headings. As the sub-title suggests, joint commitment is evidently by her lights the most fundamental social concept. As is fitting, she applies it in a wide variety of contexts, and the result is a wide-ranging and lively set of essays. Importantly, she applies her theoretical notion to questions in political philosophy and thereby connects abstract theory to real world concerns, something most theorists in this sub-field have not yet done. While many of the essays are well-known to those working in the field, it is useful to have them collected in one place, not the least because it facilitates development of an overview of her oeuvre.