This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book presents a profile of the dimensions and dynamics of the UK nursing labour market. It describes the working patterns, working hours and contracts of registered nurses. The book explains the detailed consideration to turnover, 'wastage' and workloads. The growth of employment outside the National Health Service (NHS), the emphasis on developing community based care, and organisational change in the NHS acute sector, have all impacted on the nursing labour market, as have broader economic and societal factors. The post-NHS reform creation of provider units established several hundred employing units who had greater 'freedom' and autonomy in determining nurse staffing levels and mix than had the pre-reform District Health Authorities and Boards. NHS nurses pay has, since 1983, been determined by an independent Review Body, which takes annual evidence from nursing unions and organisations, and from management.