"This assessment report establishes the value of the Hindu Kush Himalaya (HKH) for the 240 million hill and mountain people across the eight countries sharing the region, for the 1.65 billion people in the river basins downstream, and ultimately for the world. Yet, the region and its people face a range of old and new challenges moving forward, with climate change, globalization, movement of people, conflict and environmental degradation. At the same time, we also see incredible potential to meet these challenges in a sustainable manner. In spite of its importance, relatively less is known about the HKH, its ecosystems and its people, especially in the context of rapid change. Over the last few decades, there has been more research on the region, but the knowledge gathered is often scattered, reaches a limited audience, is sectoral or based on single disciplines and, most importantly, does not reach decision-makers, whether they be in government, in local communities, or in the private sector. The rationale for this assessment is manifold. The first is about extending the accessible knowledge base. There has been incredible value in bringing together people engaged in generating knowledge about the HKH to collate existing knowledge. Plus, by working across disciplines and countries, the assessment blends insights from different perspectives about the mountains. Global assessments and programmes like the Intergovernmental Panel on Climate Change (IPCC) can now benefit from an important knowledge source about this region, and the book has great value in informing global debates and discourses. Then, there is a value beyond the assessment report itself, in bringing together a network of people who can work across disciplinary and geographical boundaries in the future. But the main reason for the assessment goes beyond the collation of knowledge. It is to answer a range of policy-oriented questions we all grapple with. Some of these are quite scientific, such as what will happen with climate change, or what the impact of air pollution is. Others are more targeted to actions that people should take, like pathways to sustainable access to energy, or building resilience. The main objective of the assessment thus is to inform decision-makers with the best science and knowledge we have. This assessment has made important strides in this direction. A very important finding of the assessment is that while we have significant knowledge gaps, we know enough to take action. The publication of the Hindu Kush Himalayan Monitoring and Assessment Programme’s (HIMAP) flagship piece—The Hindu Kush Himalaya Assessment: Mountains, Climate Change, Sustainability and People—is an important milestone in a larger process that aims to bring together researchers, policy makers and the public to better manage the HKH so that women, men and children can enjoy improved well-being in a healthy mountain environment. The HIMAP process will continue to engage in science-policy discussions at country and regional levels to enhance cooperation between communities, states and countries in managing the HKH. It will also develop more targeted assessments about specific areas of concern that emerge as we develop more knowledge about the region. Importantly, the authors of the assessment have laid out mountain-specific priorities consistent with the Sustainable v Development Goals (SDGs), and this book provides an important baseline in reaching these goals for the mountains and people of the HKH region. Perhaps the greatest good is that we have an expanding community of practice working together to match and rise above the challenges facing the HKH today".....KEYWORDS: Open Access book on Hindu Kush Himalaya; Climate Change in the Hindu Kush Himalaya; Sustainable Mountain Development; Environmental Assessment; HKH Assessment Report; Biodiversity and Ecosystem Services in the HKH; Energy Needs in Asia; Water Security, Availability Use and Governance; Food Nutrition and Security in Asia; Disaster Risk Reduction and Increasing Resilience Poverty and Vulnerability in Mountain Livelihoods; Climate Change Adaptation; Governance, Drivers and Consequences of Migration; Environmental Governance in the Hindu Kush Himalaya; Sustainable Mountain Development.