Why are some individuals and groups within a society more prone to illness than others? How do we know what makes us ill? What can be done to alleviate illness or disability, and how can we be sure that an intervention will work? Biomedical scientists, doctors, statisticians, epidemiologists, sociologists, anthropologists and historians all study health and disease, but when faced with similar problems they tend to produce radically different explanations and solutions. This book describes the basic methods of investigation used by these disciplines, and shows how they are related and how they differ. The multidisciplinary team of authors brings together a wide range of expertise to provide an introduction to: social surveys, qualitative interviewing, ethnography and participant observation, historical research methods, the strategies used by demographers and epidemiologists to measure and compare disease distributions in very different populations, the concepts underlying statistical testing, experimental procedures such as randomised drug trials, the use of placebos and controls, and the key features of the scientific method in laboratory research. The book refers to examples including diabetes, hysteria, neural-tube defects and cardiovascular disease to demonstrate how the multiple interacting causes of ill health can be studied at many different levels - from microscopic processes within body cells to large-scale interactions between different groups in society. It aims to develop a critical understanding of how current knowledge has been assembled from the observations, measurements and experiments of many disciplines to provide a fuller picture of health and disease in the modern world.