Rivers are amongst the most diverse ecosystems, a source of essential services for Humanity, but also among the most endangered ecosystems on Earth. Rivers are threatened by multiple stressors, including changes in water flow, impacts on channel form, the reception of an increasing variety of novel pollutants, the overexploitation of resources, and habitat depletion. Riverine biodiversity is suffering dramatic decreases that threaten the functioning of these ecosystems and the services and benefits we obtain from them. River conservation is at the crossroad between sound science and the understanding of societal needs and policy issues. River Conservation: Challenges and Opportunities discusses the main threats faced by river ecosystems, the main socioeconomic drivers of these threats, and the possibilities to conserve and restore rivers. The main message is one of urgency: there is no time to lose to preserve a significant proportion of river biodiversity. But it is also a message of hope: rivers are the fastest ecosystems to recover from disturbance, and it is possible to restore them to healthy states. This book is addressed not only to scientists or environmentalists, but to every person interested in understanding and preserving one of the most fascinating parts of our Planet Earth