The dissertation makes a contribution toward a sociological theory of industrial relations in an attempt to explain the growing trend toward unionization among professional employees in Canada. The proposed theory identifies legally codified rule-making as the dependent variable. Four independent variables, market conditions, technology, status and ideology, are identified as the independent variables. A method for operationalizing the component variables is established and twelve hypotheses are developed to focus the investigations.

The theory is illustrated by means of three case study investigations of situations in which professional employees unionized. The case studies include an examination of the unionization of faculty members at St. Mary's University in Halifax, Nova Scotia; nurses at Mount Sinai Hospital in Toronto, Ontario and social work staff at the Catholic Children's Aid Society of Metropolitan Toronto.

The research method employed to obtain the data is a combination of library research and on-site investigations including interviews, questionnaires and an examination of both internal documentation and public documentation such as newsletters and annual reports from each of the three institutions under investigation.

The emergence of professional unions in the three different organizational settings is found to be the result of increasing strains in the workplace caused by changing markets for services, technological change, professional status concerns and ideological conflicts brought about by the creation of increasingly heterogeneous work environments. These four independent but interrelated factors all contributed to a perceived need among the professional employees to establish a body of legally codified rules, a union, to regulate behaviour in the work place.