Most of us suffer from backache at some time or other. Usually it is an unpleasant, awkward but not desperately serious problem caused by some kind of mechanical stress or damage within the back which gets better fairly quickly. This booklet aims to show you how the back works, what goes wrong, why back problems arise, how they are treated and to give some indication of when further investigations and specialist help are necessary. Backache is remarkably common. At any one time some 30 to 40 per cent of the population have backache and between 80 and 90 per cent of people experience it at some time in their lives. It affects both sexes and all ages from children to elderly people but is most prevalent in the middle years. The amount of working time lost due to back problems has increased enormously in recent years. This is now calculated as nearly £6 billion per year for the medical treatment provided, the benefits received and loss of production.