Donald G. Saari is Distinguished Professor of Mathematics and Economics and Honorary Professor of Logic and Philosophy of Science at the University of California–Irvine, where he is Director of the Institute for Mathematical Behavioral Sciences. He previously served on the faculty of Northwestern University from 1968 to 2000, where he held the Pancoe Professorship of Mathematics. A Member of the U.S. National Academy of Sciences, Fellow of the American Academy of Arts and Sciences, and Fellow of the American Association for the Advancement of Science, Professor Saari is the former Chief Editor of the Bulletin of the American Mathematical Society. The author of more than 170 published papers, he has also written numerous books, including Basic Geometry of Voting (1995), Decisions and Elections: Explaining the Unexpected (Cambridge University Press, 2001), Chaotic Elections! A Mathematician Looks at Voting (2001), The Way It Was: Mathematics from the Early Years of the Bulletin (2003), and Collisions, Rings, and Other Newtonian N-Body Problems (2005).

'The future generations of social choice theorists will certainly find much inspiration and profound insights in this book. For anyone working in the field of voting and social choice the book will provide a rich collection of results, methodological tools, and challenging open problems.' Hannu Nurmi, Academy of Finland

• 1. Subtle complexity of social choice; 2. Dethroning dictators; 3. Voting dictionaries; 4. Explaining all voting paradoxes; 5. Deliver us from plurality vote; 6. Appendix.

Donald G. Saari is Distinguished Professor of Mathematics and Economics and Honorary Professor of Logic and Philosophy of Science at the University of California–Irvine, where he is Director of the Institute for Mathematical Behavioral Sciences. He previously served on the faculty of Northwestern University from 1968 to 2000, where he held the Pancoe Professorship of Mathematics. A Member of the U.S. National Academy of Sciences, Fellow of the American Academy of Arts and Sciences, and Fellow of the American Association for the Advancement of Science, Professor Saari is the former Chief Editor of the Bulletin of the American Mathematical Society. The author of more than 170 published papers, he has also written numerous books, including Basic Geometry of Voting (1995), Decisions and Elections: Explaining the Unexpected (Cambridge University Press, 2001), Chaotic Elections! A Mathematician Looks at Voting (2001), The Way It Was: Mathematics from the Early Years of the Bulletin (2003), and Collisions, Rings, and Other Newtonian N-Body Problems (2005).

'The future generations of social choice theorists will certainly find much inspiration and profound insights in this book. For anyone working in the field of voting and social choice the book will provide a rich collection of results, methodological tools, and challenging open problems.' Hannu Nurmi, Academy of Finland

• 1. Subtle complexity of social choice; 2. Dethroning dictators; 3. Voting dictionaries; 4. Explaining all voting paradoxes; 5. Deliver us from plurality vote; 6. Appendix.

Donald G. Saari is Distinguished Professor of Mathematics and Economics and Honorary Professor of Logic and Philosophy of Science at the University of California–Irvine, where he is Director of the Institute for Mathematical Behavioral Sciences. He previously served on the faculty of Northwestern University from 1968 to 2000, where he held the Pancoe Professorship of Mathematics. A Member of the U.S. National Academy of Sciences, Fellow of the American Academy of Arts and Sciences, and Fellow of the American Association for the Advancement of Science, Professor Saari is the former Chief Editor of the Bulletin of the American Mathematical Society. The author of more than 170 published papers, he has also written numerous books, including Basic Geometry of Voting (1995), Decisions and Elections: Explaining the Unexpected (Cambridge University Press, 2001), Chaotic Elections! A Mathematician Looks at Voting (2001), The Way It Was: Mathematics from the Early Years of the Bulletin (2003), and Collisions, Rings, and Other Newtonian N-Body Problems (2005).

'The future generations of social choice theorists will certainly find much inspiration and profound insights in this book. For anyone working in the field of voting and social choice the book will provide a rich collection of results, methodological tools, and challenging open problems.' Hannu Nurmi, Academy of Finland

• 1. Subtle complexity of social choice; 2. Dethroning dictators; 3. Voting dictionaries; 4. Explaining all voting paradoxes; 5. Deliver us from plurality vote; 6. Appendix.