This encyclopedia presents a concise introduction to “law and economics”, a field that is thriving, continuously evolving. While other valuable resources already exist providing a number of essays on given topics, this encyclopedia is original, differing from – and complementing – the other encyclopedias and companions that have been published in four respects. First, in order to cover as many aspects and dimensions of law and economics it consists of a large number of chapters that are rather of short size. Second, a large number of these chapters are at the limits of law and economics and other fields that are close to law and economics – public choice, institutional economics, transaction cost economics, industrial economics, etc. Third, we also chose to make room to historical and methodological chapters about the founders of the field and about some of the important scholars who, directly or indirectly, contributed to make law and economics what it became. This new edition aims atexpanding these specificities. The goal is to cover even more areas in law and economics – in particular, focusing on the problems raised by big data and new technologies; to deepen the interdisciplinary dimension of the field and to include more historical and methodological chapters.