The practice of occupational health has always been, and continues to be, concerned with the two way relationship between work and health. It deals as much with the impact of work and working conditions on causes of ill health as it does with illness, injury or disability of the individual in determining a person's capacity for work activities. The chapter explains the relationship between health and work in the context of the public health. Towards the end of the 19th century a small group of enlightened philanthropic employers provided healthcare for their employees, and sometimes their families, in the days before a national health service. So in the years running up to the Second World War there was the provision of a comprehensive health service that dealt with the prevention of occupational disease, the treatment and management of both occupational and non-occupational disease and the rehabilitation of ill or injured workers back to employment.