In the last decades, the hydrology and water management sectors have been dealing with global changes, proposing several innovative solutions. Climate changes are leading to an increase of long hot and dry periods, alternated by short and intense rainfall events. Urban areas are particularly vulnerable to these changes: rapid population growth and intense anthropic activity enhance the risk of extreme hydrological events. Several solutions have been proposed in the last years to monitor, prevent, forecast and mitigate rainfall extremes and their effects in natural and urban environments. Some questions, however, remain unsolved and new issues are challenging the hydrological community. The inter- and multidisciplinary aims and topics discussed in the chapters of this book are organised into the following three main topics: (1) Climate change and geo-hydrological risk, (2) Tools and techniques for improving the comprehension of catchment hydrology and river hydraulics, and (3) Sustainable use of water resources. In Focus - a book series that showcases the latest accomplishments in water research. Each book focuses on a specialist area with papers from top experts in the field. It aims to be a vehicle for in-depth understanding and inspire further conversations in the sector.