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: an overview of the subject's historical development, a discussion of the ethical aspects of social choice, a study of the algebraic and combinatorial aspects of social choice theory, and an application of mathematic theory to several case studies.