Desertification figures prominently in environmental debates, as well as in peace studies with its recent focus on climatic events and conflict. This book provides a comprehensive, updated, and critical overview of the concept of desertification. It is very useful in understanding the natural science on the subject, but equally valuable for grasping the larger sociopolitical nexus. Some chapters (5, 9, and 10) provide state-of-the-art surveys on the overarching natural science basis of vegetation and degradation trends, pointing out the importance of integrating remote-sensing data with ground-verified time-series and perceptions of the local population. Case-studies from Niger, Mali, US, Ethiopia, Patagonia, the Andes, southern Europe, and Central Asia (chs. 6, 7, 12, 13, 14, 16, and 17 respectively) offer local data analysis. One key, yet unsurprising, lesson from these chapters is that the type of ecosystem matters quite a lot for what kind of degradation is likely. Another is the very variable basis for claiming widespread degradation, but also that certain forms of degradation are undeniably quite substantial. In view of the lack of universal desertification – in itself not a new observation – the chapters that deal with the history of the concept, its narrative stickiness, and how policies have been formed accordingly are particularly valuable for understanding social processes (chs. 2, 3, 4, 8, 11, 15, 18, and 19). Together with chapter 20, these chapters are quite consensual with regards to policy recommendations – empowering people in drylands, marrying science with local knowledge and institutions, ensuring mobility and market access, dropping the term desertification in favor of more homogenous and nuanced terms, and finally acknowledging that change is here to stay and that positive adjustment is more useful than resistance.