Under Approval Voting, voters can ''approve" as many candidates as they want, and the candidate approved by the largest number of voters is elected. Since the publication of the seminal book written by Steven Brams and Peter Fishburn in 1983, a variety of theoretical and empirical works have enhanced our understanding of this method. The behavior of voters in such elections has been observed both in the laboratory and in the field; social choice theorists have analyzed the method from the axiomatic point of view; game theory and computer science have been used to scrutinize various strategic aspects; and political scientists have considered the structure of electoral competition entailed by Approval Voting. This book surveys this large body of knowledge through a collection of contributions written by specialists of the various disciplines involved.

Zusammenfassung
I am honoredto write a prefaceto this remarkablybroadand comprehensivevolume on approval voting (AV). It has been almost 35 years since Peter C. Fishburn and I met in 1976 and began research on AV. Besides my 30-year collaboration with Fishburn, I have collaborated with several other scholars including D. Marc Kilgour,SamuelMerrill,JackH.Nagel,M.RemziSanver,andWilliamS.Zwicker on AV-related research. Over these years there has been a profusion of articles and books reporting on empirical and theoretical aspects of AV and their normative implications. This volume touches on all aspects of this research and will be a very helpful sourcebook to scholars who want to carry this research forward. In Brams and Fishburn (1983/2007, p. 172), Fishburn and I were unabashed in our support of AV: Approval voting strikes at the heart of how political debate is resolved. It offers a new approach to the realization of democratic principles by rede ning what constitutes a de- cratic choice. Indeed, the foundation on which representative government is built is periodic elections, and the central problem of elections today is how to translate voter preferences, with as little distortion as possible, into consensus choices in multicandidate races. We believe that approval voting is the best practical way for amalgamating these preferences, fairlyand impartially,toproduce awinnerand thereby amelioratethemulticandateproblem.

Inhalt
to the Handbook on Approval Voting.- History of Approval Voting.- Acclamation Voting in Sparta: An Early Use of Approval Voting.- Going from Theory to Practice: The Mixed Success of Approval Voting.- Axiomatic Theory.- Collective Choice for Simple Preferences.- Axiomatizations of Approval Voting.- Committees.- Approval Balloting for Multi-winner Elections.- Does Choosing Committees from Approval Balloting Fulfill the Electorate's Will?.- Strategic Voting.- The Basic Approval Voting Game.- Approval Voting in Large Electorates.- Computational Aspects of Approval Voting.- Probabilistic Exercises.- On the Condorcet Efficiency of Approval Voting and Extended Scoring Rules for Three Alternatives.- Behavioral Heterogeneity Under Approval and Plurality Voting.- In Silico Voting Experiments.- Experiments.- Laboratory Experiments on Approval Voting.- Framed Field Experiments on Approval Voting: Lessons from the 2002 and 2007 French Presidential Elections.- Approval Voting in Germany: Description of a Field Experiment.- Electoral Competition.- Classical Electoral Competition Under Approval Voting.- Policy Moderation and Endogenous Candidacy in Approval Voting Elections.- Meaning for Individual and Society.- Describing Society Through Approval Data.- Approval as an Intrinsic Part of Preference.