A most comprehensive survey of recent research in an important area of social choice theory.Offering the most comprehensive and up-to-date survey of current research in an important area of social choice theory, Wulf Gaertner's monograph provides an essential reference for economists and political scientists. In the interests of accessibilty and readability extensive formal proofs to theorems are not included in the text but are carefully referenced, allowing interested readers to follow up themselves. Though written in a formal style, the mathematical level of the book is designed to be appropriate for graduate students with a basic training in mathematics.Offering the most comprehensive and up-to-date survey of current research in an important area of social choice theory, Wulf Gaertner's monograph provides an essential reference for economists and political scientists. In the interests of accessibilty and readability extensive formal proofs to theorems are not included in the text but are carefully referenced, allowing interested readers to follow up themselves. Though written in a formal style, the mathematical level of the book is designed to be appropriate for graduate students with a basic training in mathematics.Offering the most comprehensive and up-to-date survey of current research in an important area of social choice theory, Wulf Gaertner's monograph provides an essential reference for economists and political scientists. In the interests of accessibilty and readability, extensive formal proofs to theorems are not included in the text but are carefully referenced, allowing interested readers to pursue them independently. Though written in a formal style, the mathematical level of the book is designed to be appropriate for graduate students with a basic training in mathematics.Preface and acknowledgements; 1. Introduction; 2. Notation, definitions and two fundamental theorems; 3. The existence of collective choice rules under exclusion conditions for finl£