The book aims to face the challenge of post-COVID-19 dynamics toward green and digital transition, between metropolitan and return to villages' perspectives. It presents a multi-disciplinary scientific debate on the new frontiers of strategic and spatial planning, economic programs and decision support tools, within the urban-rural areas networks and the metropolitan cities. The book focuses on six topics: inner and marginalized areas local development to re-balance territorial inequalities; knowledge and innovation ecosystem for urban regeneration and resilience; metropolitan cities and territorial dynamics; rules, governance, economy, society; green buildings, post-carbon city and ecosystem services; infrastructures and spatial information systems; cultural heritage: conservation, enhancement and management. In addition, the book hosts a Special Section: Rhegion United Nations 2020-2030. The book will benefit all researchers, practitioners and policymakers interested in the issues applied to metropolitan cities and marginal areas.