More complex political institutions produce more stable and socially efficient the outcomes; this book develops an extensive analysis of that relationship. It explores concepts, questions, and insights based on social choice theory, focusing on more than forty democratic countries and several international organizations from late medieval times to the present.

Personal representation is an essential element to achieve a high quality of democracy. Many studies of electoral systems, by focusing on the allocation of seats to parties, have neglected the study of this essential dimension. In democratic countries a huge variety of ballot forms and rules exist to vote for individual candidates and to allocate seats. This book studies different voting procedures and formulas for personal representation, their origins and consequences, their compatibility with party representation and the strategies and normative criteria for electoral system choice.