This book presents an overview of recent developments in social choice theory and welfare economics, drawn from the proceedings of the eighth conference in the International Symposia in Economic Theory and Econometrics series under the general editorship of William Barnett. The volume is divided into four parts, each exploring broad themes in social choice theory and welfare economics. First, an overview of the short, yet intense, period of the subject’s historical development. Second, a discussion of the ethical aspects of social choice, encompassing such issues as equal opportunity, individual rights, and population monotonicity. Third, a study of the algebraic and combinatorial aspects of social choice theory. The final section is devoted to a study of aggregation with risk aversion to current and future variables, and the creation of an intertemporal framework to go beyond the usual static description of income distributions measured over a short period.