The mountainous areas of Southeast Asia are undergoing rapid change. For centuries these areas were characterized by forests, isolation, and the presence of ethnic minority people who subsisted on rotational swidden agriculture. Although such conditions can still be found in certain places today, they are no longer representative of the situation across many of these areas. Forest areas have reduced, road networks have expanded into the mountains, and the younger generations of the ethnic minorities have increasingly moved to urban areas. In addition, traditional swidden agriculture has been replaced with intensified swiddening systems that use shorter fallow periods and also permanent fields, and farmers are increasingly using irrigation and agrochemicals—finding themselves a part of modern supply chains delivering raw materials and food to urban areas. This book provides an interdisciplinary account of the drivers and consequences, both positive and negative, of land use change in these mountainous areas, and of the technical and social innovations and policy strategies used to promote the positive effects of these changes, while at the same time trying to limit the adverse effects.