This thesis sets out to account for the relative failure of Total Quality Management (TQM) experiments installed in the NHS between 1990 and 1994. In the study, only two NHS pilot sites in a large sample of hospitals and community services were found to have made significant progress on implementing TQM. Whilst most of these TQM sites made more progress on structured quality improvement than a group of non-TQM NHS quasi-controls, all were outperformed by two commercial TQM companies in the sample. The analysis is based on 850 semi-structured interviews carried out with a wide range of staff as well as documentary analysis, non-participant observation, and feedback workshops at selected sites. In accounting for the results, the thesis tests eight propositions about the application of rationalistic private sector models of change to a complex public sector organisation like the NHS. The analysis demonstrates the limitations of such approaches when they are not adapted to take account of the technical, systemic and behavioural differences between the two sectors. It can also be said that funding for the NHS experiments, whilst substantial, was an order of magnitude lower than that in the commercial companies. Similarly, support both centrally and locally in the NHS was not sufficient to provide for rigorous pre-planning and monitoring of progress. Numerous other changes being made at the same time were mostly incompatible with TQM principles and hindered progress on coherent change. Leadership commitment to, and understanding of, TQM was much weaker in the NHS than in the commercial companies. The requirement to move towards collective, userdefined, measures of quality met with opposition from staff groups who were used to their own individualistic and professional conceptions of quality. This led to NHS TQM sites being unable to demonstrate the organisation-wide changes that are said to be hallmarks of TQM.