This is a textbook introducing selected topics in formal social choice theory. Social choice theory studies group choices that are based on information about preferences of members of the group (voting rules being one important special case). This involves economics, which provides the method of modelling individual decision making; political philosophy, which provides criteria about the allocation of decision-influencing power; and game theory, which provides a framework for thinking about the strategies individuals employ in trying to influence the group choice. The goal of this book is to...