Any enterprise of this nature is an inevitable compromise between alternatives. In the present case it is also a compromise between a theoretical interest in the sociological postulate of role, and a personal involvement in the study of behaviour in educational settings. Selection of a research topic should not, however, proceed simply from serendipitous circumstance or from a whim of the author. It must be justified in terms of its potential contribution to the disciplines whose perspectives are employed. The current study is justified by appeal to two criteria, one sociological, the other educational. Firstly, although the concepts of role and role set are widely accepted in sociological theory, surprisingly few investigations have been designed to explore their theoretical implications. Secondly, there has been, until very recently, a marked lack in educational discussion of both theory and empirical analysis concerned with the effects of the structural properties of educational settings on the expectations and performance of personnel. The present investigation is intended to contribute to the discussion of both issues. The organisation of the thesis is a direct result of this intention. Chapter I is concerned with the theoretical problems of consensus and disensus associated with the concepts of role and role set. Charter II applies the general theoretical perspective to a specific educational setting. Chapter III elaborates a research model appropriate to the empirical investigation of disensus in the role set of the teacher. Chapter IV describes the development of the measurement instrument and the general methodological procedures employed. Chapter V presents the findings and Chapter VI discusses the implications of the findings for the theoretical position outlined in Chapters I and II. It also suggests various supplementary analyses which might serve to further clarify the sociological and educational implications of the study of disensus in the role set of the teacher.