Epidemiology originated during the Middle Ages when science-based medicine arose and medical schools were established. Clinically trained epidemiologists began to advance knowledge on human disease through intensive observations of their patients over time. Modern computing was quickly adopted by epidemiologists as an essential tool of modern medicine. Despite its key role in medicine, epidemiology-based teaching and research is now faltering, as professors emphasize the difficulties, rather than the advantages, of this critical branch of medicine. No other medical specialty can accurately track diseases in populations at risk, or evaluate the cost and quality of medical care. It can create clinical information systems for practising physicians, assess health risks in large population groups and evaluate unique subgroups at risk of disease. A major lesson from the COVID-19 experience is that enhancing the work of medical epidemiologists is crucial to the future of public health and clinical medicine. How this goal can be achieved is the central theme of this volume.