Since its first publication in 1933, Clay’s Handbook of Environmental Health (under its different names) has provided a definitive guide for the environmental health practitioner (EHP), and an essential reference for the consultant and student. This 22nd edition continues with its more recent successful structure, reviewing the core principles, techniques, competencies and skills required of an EHP, and then outlining the specialist subjects without getting bogged down in a legalistic approach, seeking to broaden the content for a more global audience. This new edition seeks to educate the EHP on the public health impacts of global heating and the climate emergency and also reflects the COVID-19 pandemic, as might be expected. Although seeking to have global appeal, the impact of the UK leaving the EU is also addressed. The book examines environmental health in different settings, including in the military, working in both conflict and natural disaster settings, and environmental health at sea and airports. In line with previous editions, case studies are used to illustrate how EH problems have been resolved. This new edition includes guidance on key issues in public and environmental health including air pollution, contaminated land, housing and health, noise, water, food safety, pests and vector control, chemicals in the environment and radiation, as well as sustainability and public health and humanitarian crises. This handbook aims to give a basic understanding of the philosophical basis of environmental health, as well as the required technical aspects and an understanding of environmental health in different settings. All chapters have sections on further reading and sources of information. Clay’s Handbook is essential reading for all practitioners, students and researchers in environmental and public health wherever they are working.