"Welfare Economics and Social Choice Theory" offers a comprehensive analysis of the central themes of welfare economics and social choice theory. The book addresses fundamental concepts such as general equilibrium models, Pareto optimality, uncertainties, externalities, and public goods. Additionally, it covers important aspects of social choice theory, including compensation criteria, fairness, and voting. The underlying question of the work is whether certain economic or voting mechanisms are beneficial or detrimental to society. This second edition updates the content of the first edition and adds new chapters that deepen the understanding of the topics. The book is aimed at students of economics who already have a basic knowledge of microeconomics, but it is also of interest to graduates and professionals seeking an overview of the results of welfare economics and social choice theory without getting lost in technical details.