This paper examines the phenomenon of private-practice teachers in public schools. It helps frame the debates surrounding market-driven reforms that are aimed at freeing schools from bureaucratic control and raises several questions about the potential impact of private-practice teachers. It asks whether market-driven reforms within public schools allow for a new type of teacher professionalism, whether privatization efforts for teachers are replacing public bureaucracies with private bureaucracies, and whether there are competing conceptions of professionalism that are better suited to new organizational arrangements. The paper draws on the results of recent privatization efforts to study the complex intersection between teacher professionalism and school organization. It claims that the debate concerning private-practice teaching is central to understanding school improvement, positing that private-practice teachers will be in greater demand to meet widespread teacher shortages. The paper looks at school organization and teacher professionalization and how these affect each other, paying special attention to teacher professionalization, what is meant by that term, and the impact market pressures will bring to bear on the balance and nature of bureaucratic versus professional control. (Contains 46 references.) (RJM)