This is an accessible, easily readable, and modern introduction to epidemiology for students of medicine and public health. It combines a strong public health perspective and rationale with modern methodological insights in a coherent and straight forward way. It emphasises the fundamental principles common to all areas of epidemiology and, unlike many other texts, integrates both public health and clinical epidemiology and the study of infectious and chronic diseases. It aims to give health professionals a good understanding of the methods and potential problems underlying epidemiological data and reports but also provides a thorough introduction for would-be epidemiologists. The 'nuts and bolts' of epidemiology are embedded in the wider health perspective and the concluding chapter explores future possibilities and emphasises the integration of the various strands of the discipline. The basic messages are reinforced through numerous examples and questions, with answers provided.