It gives us great pleasure to write the preface to this book, the second in the series of monographs produced by the European Academy of Rehabilitation Medicine. No part of medicine, no clinical intervention, is complete without thinking about its effect on the person life and the quality thereof. One of the most powerful determinants of this is work; a source not only of income, but of satisfaction and a sense of purpose and worth. The Academy, founded in 1969, is composed of senior European doctors spec- lising in Rehabilitation and Physical Medicine. It meets regularly to discuss matters of importance in the field, including teaching, research and ethical matters. It recognises that the ability of the speciality and of related ones to decrease dependency and increase autonomy and quality of life needs to be better known. Hence the production of these monographs. They will help readers access a vast amount of literature on the practice of rehabilitation and its effectiveness. Theyshould be particularly useful to young doctors preparing for the European Boards certification in Physical and Rehabilitation Medicine as they are authoritative and cover subjects in depth. Topics covered in the series range from basic sciences to the most applied areas.