Epidemiology is the study of the distribution and causation of disease in human populations. It has always been part of the curriculum for medical students, but not ranked highly by them in terms of interest or importance. However, recent GMC recommendations for change in the UK medical curricula include an increase in emphasis in the study of epidemiology and public health medicine, so the subject is likely to take higher priority in the future. This new edition of one of the best known student textbooks of epidemiology has been updated and includes new material while still offering concise coverage of the core knowledge required by the student.