The COVID-19 pandemic demonstrated the necessity for highly interdisciplinary, multi-stakeholder collaboration to enable effective public health practice and response. The application of wastewater monitoring to support the pandemic response was demonstrated quickly, leveraging existing scientific and engineering capability to develop rapidly methods that enabled scaling of monitoring programmes across the globe. The science and practice of wastewater monitoring, or wastewater-based epidemiology (WBE) as it is often termed in the context of surveillance, for public health threats is well-documented. As a highly socialised tool, national, regional and international communities of interest have joined efforts to provide evidence of the value of the data derived and its application in practice. While the use of wastewater monitoring to detect and characterise targets of public health concern is not new, COVID-19 and the (re)emergence of rare, novel or unexpected pathogens stresses the importance of continued research and development into the utility of wastewater monitoring and utility of the data it generates. As wastewater monitoring continues to move from the research community into applied public health agencies, there is a need to develop standard methods and data analytics for specific applications. Establishing WBE at the frontier of global public health requires a clearer understanding and acknowledgment of its value by public health policy makers, regulators and government.This book presents a broad view of WBE thinking and practice, delineating the current understanding and future potential of the field. The topics covered range from geographically distinct reports on the use of WBE to inform on pathogen circulation in a population, through technical developments and data utility, to commentaries on future challenges and opportunities including for WBE beyond the pandemic.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 to inspire further conversations in the sector.