Back pain is one of the most common reasons for chronic disability and incapacity for work in adults of working age and is a good example of current social security problems. From a health care perspective, back pain is not a disease but a common bodily symptom, and chronic low back disability depends more on psychosocial factors than on physical pathology. From an epidemiological perspective, back pain is not a discrete health problem, but is often associated with other pains, co-morbidities, psychological and stress-related symptoms, and work-related or other social problems. From a social perspective, trends of incapacity for work attributed to back pain and social security benefits paid for back pain form a social phenomenon which is related to the economic and labour market situation. These perspectives are not mutually exclusive, but may represent different views of a complex set of inter-acting forces. What is beyond dispute is that from a social security perspective, back pain is not simply a health problem, but often raises more fundamental psychosocial issues. This book provides a comprehensive review of the scientific and social security literature, and social security statistics on back pain in various EU and OECD countries. This evidence is then integrated with a modern, biopsychosocial model of pain and disability to provide a factual and theoretical background to the debate on disability and incapacity benefits. Some of the issues raised may be equally relevant to other common social security problems such as musculoskeletal complaints, stress-related disorders and chronic fatigue.