**Preface to "Sustainable Lighting & Lighting for Sustainability"**

This book is the result of two years of hard work. After the success of the Special Issues "Sustainable Lighting and Energy Saving" (2018), and "Lighting at the Frontiers of Sustainable Development" (2019), MDPI kindly asked me to make a selection for the present book, which aims to summarize the conclusions of both Special Issues.

Given the quality and originality of the 28 published papers, the choice has been rather complex. I, in no way, pretend to have selected the best papers because, honestly, they were impossible to rank. My task here was to demonstrate that a new perspective of lighting, what I call total lighting, may have arisen from these two Special Issues. Thus, I had to make coherent choices so that the selected papers and their order in the book sent a message to the reader.

With this target in mind, I selected twelve articles, six of which deal with what we classically call "sustainable lighting" (light pollution and the optimization of indoor and outdoor lighting). Meanwhile, the six other papers belong to what could be best described as "lighting for sustainability", the way in which accurate and smart lighting can ensure the availability of resources for the future generations. In this category I selected articles dealing with the use of lighting to improve agrarian production, the attachment of people to traditional ways of life, and the preservation of cultural heritage. These fields are closely and indisputably related to migration, cultural identity, well-being and equality, hot topics for the achievement of the 17 Sustainable Development Goals. As demonstrated in the two aforementioned Special Issues, particularly that of "Lighting at the Frontiers of Sustainable Development" (2019), lighting can provide a new perspective in all these new areas.

I hope this book linking sustainable lighting with lighting for sustainability will contribute to an understanding of their key roles in the path to truly sustainable development.
