Dear Colleagues, In developed countries, the traditional agrarian vision of the rural world, which univocally identified as agrarian and rural, has given way to a multifunctional approach to this space. In the 1990s, the European Commission, through the then novel Leader Initiative, launched rural development programmes, whose main objective was economic diversification based on the development of new recreational, touristic or agro-industrial uses that were emerging. Often, the modest size of the investments associated with these programmes and their participatory development models ensured that these projects were implemented in a harmonious way in economic, social and environmental terms. However, there is now a growing interest in other types of investment in rural areas, such as renewable energies (wind farms, photovoltaic plants), diffuse industrialisation projects and even the extraction and processing of strategic minerals. These types of investments can be valuable alternatives for achieving the longed-for economic diversification, although it is no less true that they involve abruptly altering the traditional agricultural and livestock uses of the rural environment. The purpose of this Special Issue is to provide scientific and academic evidence regarding the implementation of these two types of projects: their long-term viability, their impact on the demographic and economic structures of the regions or districts in which they are implemented and the change in traditional land uses, as well as any other indicators related to the socio-economic development of these environments. In this endeavour, all types of case studies are welcome, which, based on different methodological approaches, approach the subject under study, both in developed countries and developing regions of the world affected by the same problems.
