This book provides a systematic and comprehensive survey and evaluation of the problems of incorporating individual and group rights and values into social procedures and judgements, and examines the solutions that have been proposed. The book begins by defending the presence of libertarian requirements in social choice. A framework for incorporating individual rights into social choice is then formally presented, and libertarian conditions are formulated which can be satisfied for all conceivable sets of individual preferences. Further chapters then show how such libertarian conditions can conflict with other well-known social conditions in social choice, in particular the Pareto condition. Resolution approaches to this latter conflict are evaluated, and are shown not to be appropriate for all types of conflict environments. Instead a more pragmatic approach is called for, based on more information regarding the environment from which choice is to be made.