The book provides an in-depth analysis of regulations and legal frameworks related to sustainability and sustainable finance, with a particular focus on the European Union and Italy. The first chapter explores the legal sources of regulation, including the Brundtland Report, the 2030 Agenda for Sustainable Development, and the European Green Deal. It also examines the European Regulation 2020/852 on the sustainable taxonomy and aspects related to Environmental, Social, and Governance (ESG) factors. The second chapter discusses sustainable finance, providing an overview of the EU Commission's action plan and regulations on sustainable financial services, such as the SFDR. The third chapter addresses corporate social responsibility (CSR) and sustainability governance. The fourth chapter analyzes the implementation of EU directives in the Italian legal system, with a focus on the Consob regulation on non-financial information disclosure. The book concludes with a study on the reshaping of social interest in different jurisdictions, with a focus on France.