Social epistemology has been flourishing in recent years, expanding and making connections with political philosophy, virtue epistemology, philosophy of science, and feminist philosophy. The philosophy of the social world too is flourishing, with burgeoning work in the metaphysics of thesocial world, collective responsibility, group action, and group belief. The new philosophical vista now more clearly presenting itself is collective epistemology- - the epistemology of groups and institutions. Groups engage in epistemic activity all the time--whether it be the active collective inquiry of scientific research groups or crime detection units, or the evidential deliberations of tribunals and juries, or the informational efforts of the voting population in general--and yet in philosophy thereis still relatively little epistemology of groups to help explore these epistemic practices and their various dimensions of social and philosophical significance. The aim of this book is to address this lack, by presenting original essays in the field of collective epistemology, exploring theseregions of epistemic practice and their significance for Epistemology, Political Philosophy, Ethics, and the Philosophy of Science.