Changing times place new demands on those involved in the implementation of construction projects. Within a relatively few years, the size and complexity of projects has grown substantially. Environmental and other public and social considerations are increasingly significant. With growing complexity, the requirements for effective project management and control of schedule, cost, and quality have also multiplied. The use of multiple construction materials and equipment contracts has flourished in order to phase construction, compress schedules, and improve performance. In short, the task of achieving the objectives of construction projects has become more difficult. As a result, there has been significant re-evaluation and experimentation with the roles and scopes of service provided by the various organizations involved in construction projects. The traditional roles of the owner, architect-engineer, and contractors have too frequently failed to achieve desired results. Wide variations in these traditional roles have been tried in varied circumstances with mixed results. From this experimentation, reasonably well-defined roles for the project manager, design manager, and construction manager are emerging. These professional service roles, properly executed, provide the means for improving overall performance of the project and construction team. They also afford an opportunity for expanded professional service to clients by consulting firms. (Author)