This volume is a conceptual analysis of issues in group responsibility. An attempt is made to identify factors which affect the degree to which individuals sharing responsibility for what happens bear responsibility for it, as well as factors which are erroneously judged to have such an effect. An examination of these issues leads to extended discussions of acting or failing to act in the company of others, the sequence in which the agents in a group perform acts, and group risk taking. It is argued that the failure to understand such issues has contributed to a widespread uncertainty in contemporary society as to the moral implications of participating in group actions.