Following the success of the fourth edition, which was highly commended in the primary health care category for the 2018 British Medical Association (BMA) Medical Book Awards, this fifth edition has been substantially revised and updated to reflect significant changes in health care practice and to incorporate the explosion of information since the advent of the fourth industrial revolution and the COVID-19 pandemic. As before, the book covers target organ systems that can be affected by hazardous exposures in traditional industries and modern workplaces, both of which coexist in different parts of the world and present unique occupational health challenges for the medical practitioner. To this end, this reference textbook focuses on the clinical presentations, investigations, and medical and work-centric management of affected individuals. We have retained consideration of some special issues relevant to occupational medicine practice in this new edition and included a new section relating to the multidisciplinary nature of occupational health practice.The main emphasis continues to be prevention of disease and early detection of health effects caused by work exposures. This edition of the book has been updated to include new information and references. We have kept some of the previous case studies and illustrations, and introduced several new ones, some of which reflect the changes of practice due to the COVID-19 pandemic — for example, in risk communication, recognition and management of the risks of health care and frontline work. We have again asked international experts in occupational medicine and cross-disciplinary medical specialties to jointly author many of the chapters. Some of the authors are from Asia, and others from Europe, the United States, United Kingdom and Australia. All the authors have either clinical and/or academic experience in, or related to occupational medicine practice.The book is targeted at all those who are interested in the interaction between work and health, and how occupational diseases and work-related disorders may present and be managed. It will be of interest to medical practitioners, especially those in primary care and doctors intending to pursue a career in occupational medicine. It would also be relevant for allied health and safety professionals wanting to know more about health effects resulting from occupational exposures. Other groups who may find this edition useful as a ready reference are medical students, occupational health nurses, or clinical specialists in diverse fields such as dermatology, respiratory medicine, infectious diseases or toxicology.