The purpose of this thesis is to develop a model of the role of a senior management services officer in one part of the National Health Service. It puts forward and discusses the deficiencies of other models of this role in order to identify parts of the role which a new model must seek to describe more adequately. The main parts of the role explored can be described as political and the expertise required to carry them out is usually said to be based on experience. The model put forward in the thesis is a two part model. The first part consists of a set of categories which describe the events which make up all the various aspects of the activities of a management services officer. The general properties and characteristics of these event categories are developed. The second part of the model is concerned with how such events fit together into projects. The main theme of this fitting together of events is the negotiation of order in large complex organisations. The model is based on a record of the change agent activities of one management services officer over a long period of time. Because of the present lack of understanding of this role and in order to include a wide variety of events in the analysis, an unstructured data collection method was used. Qualitative data is used in this study and appropriate grounded theory data analysis methods are used in the analysis. The generality of this model outside the context in which it has been developed is discussed.