1. Introductory Sections.- Multiperson Decision Making: a Selective Review.- Fuzzy Set Theory as a Theory of Vagueness.- Vague Notions in the Theory of Voting.- 2. General Issues Related to Decision Making under Fuzziness.- Aggregation of Possibility Measures.- Modelling Valued Preference Relations.- Revealed Fuzzy Preferences.- Categories of Fuzzy Relations in Decision Making.- Determination and Interpretation of the Fuzzy Utility of an Act in an Uncertain Environment.- Extending Aggregation Operators for Multicriteria Decision Making.- Ranking Alternatives by Weak Transitivity Relations.- Calculating the Mean Knowledge Representation from Multiple Experts.- An Approach to Customized End-User Views in Multi-User Information Retrieval Systems.- 3. Group Decision Making under Fuzziness.- Means and Social Welfare Functions in Fuzzy Binary Relation Spaces.- Aggregation of Fuzzy Preferences.- Single - Peakedness in Weighted Aggregation of Fuzzy Opinions in a Fuzzy Group.- On Group Decision Making under Fuzzy Preferences.- Group Decision Making with Fuzzy and Non-Fuzzy Evaluations.- On Construction of the Fuzzy Multiattribute Risk Function for Group Decision Making.- Consensus Measures for Qualitative Order Relations.- On a Consensus Measure in a Group MCDM Problem.- Voting Procedures with a priori Incomplete Individual Profiles.- 4. Team Decision Making under Fuzziness.- A Team Decision Making Model for Distributed Problem Solving.- Evidential Teams.- 5. Fuzzy Games.- Fuzzy Goals and Sets of Choices in Two-Person Games.- Playing Matrix Games Defined by Linguistic Labels.- Fuzzy Convexity and Peripherial Core of an Exchange Economy Represented as a Fuzzy Game.- Fuzzy Sequencing Games.