The various contributions gathered in this book lay the groundwork for a reflection on the wastelands, from identification to analysis of the modalities of reconversion, through different geographical contexts, focusing on the renewed stakes with territorial projects that challenge sustainability and challenge development policies. It is a question of taking the measure of the wastelands to see to what extent it is possible to revitalize these former industrial sites and other urban wastelands, to examine the conditions of intervention and to evaluate the prospects of economic, environmental and social viability.