This special issue contains the proceedings of the 12th Annual Seminar organized by the FONCIMED Network in Corte, Corsica, in October 2020. The international conference dealt with current developments in Mediterranean mountain land heritage in the context of contemporary social and environmental concerns. The issue’s 14 articles relate to the three shores of the Mediterranean and its islands. In their Introduction, the journal’s coordinators arrange the contributions within a single model for the Mediterranean mountain agrarian system. In this tiered model, irrigated piedmonts, managed slopes and high mountain pastures have been the basis for densification of human population and the complexity of rural land tenure until the very recent abandonment of agriculture, everywhere visible; and contemporary redevelopment is marked by continuity (the connection between the land and its original inhabitants) and disruption (the development of tourism and residential transformation). The first section of the book, entitled “Abandoning mountainous areas and disrupting the synergy between slopes and flatlands”, addresses the utilization of space and the place given to agricultural activities, that public policies tend to view as “problems”. The section under the heading “Loopholes in land rights, interconnections between rights” groups together texts which explore in detail the ways in which land rights are used and the extreme flexibility that actors have created to enable them to set up new systems of intervention associating agriculture with new forms of activity. Finally, in the last section, entitled “Reclaim spaces to restore agricultural practices”, the papers deal with attempts at rehabilitation, at project level and in often innovative social contexts, including both the obstacles they encounter and the land solutions they come up with,