Examining the ontological nature of social groups and the way in which groups should be regarded within moral deliberation this book makes an original contribution to the field of social philosophy. It tackles the fundamental metaphysical question that has either been ignored or unsatisfactorily addressed: 'what kind of thing is a social group?' Sheehy argues for an ontological realism about groups, defending the thesis that groups are composite material particulars, ontologically on a par with individuals and capable of figuring in their own right in descriptions and explanations. He then goes on to discuss the practical and moral question of whether groups can be regarded as the bearers of moral status, rights and moral judgements.