Stephanie Collins’ Group Duties offers interesting new arguments and brings together numerous interconnected issues that have hitherto been treated separately. My critical commentary focuses on two particularly original and central claims of the book: (1) Only groups that are united under a group-level decision-making procedure can bear duties. (2) Attributions of duties to other groups should be understood as attributions of “coordination duties” to each member of the group, duties to either take steps responsive to the others with a view to the group’s doing what is said to be its duty or to express willingness to do so. In support of the first claim, Collins argues that only groups that can make decisions can bear duties, and that the ab...