O n behalf of the World Tourism Organization (UNWTO), the United Nations Specialized Agency for tourism, I am pleased to introduce this publication by the Estoril Higher Institute for Tourism and Hotel Studies (ESHTE), the INATEL Foundation and Entidade Regional de Turismo do Alentejo outlining the emerging notion of Sustainable Tourism Law. I wish to thank both ESHTE and INATEL for once again making an important contribution to the academic knowledge base on travel and tourism. The historic 2015 agreement among world leaders at the United Nations on a universal 2030 Agenda for Sustainable Development committed 196 countries to pursue a set of 17 Sustainable Development Goals (SDGs) leading to a better future for all. The shift from commitment to action can only be achieved if sustainable development moves from the periphery to the core of decision-making in both public and private domains. Tourism is included as part of three SDGs – Goal 8 on economic growth and jobs; Goal 12 on sustainable production and consumption and Goal 14 on Life below water. Yet, sustainable tourism can and must play a significant role in delivering solutions through the framework of all 17 SDGs. Portugal is aiming to develop an economically, socially and environmentally sustainable tourism sector over the next decade as part of its Tourism Strategy 2017-2027. With ambitions such as doubling tourism revenues, increasing tourism education programmes, ensuring local community benefits, and encouraging more than 90% of tourism companies to adopt responsible consumption and production practices, the Strategy can make Portugal one of the world’s most sustainable and competitive destinations. This book outlines the legal basis behind which sustainable tourism policies and practices can be implemented both in and outside Portugal. It features key scholarly texts, several of which from the Sustainable Tourism Law conference that was held in Estoril, Lisbon and Evora on 9-10 October 2017 as part of the celebrations of the 2017 International Year of Sustainable Tourism for Development.