Schooled to oversee fixed, almost unvarying routines, managers today are unprepared to manage the conflicts in modern work flow relationships. The demand for more and quicker responsiveness to customers, market, product, and process changes means there are few ""routine"" technologies left to manage. The modern line manager, according to Sayles, must be a ""working leader,"" managing work flow relationships on the boundaries between jobs, functions, departments; making things ""work"" through trade-offs with superiors and peers. The working leader has an agenda, knows the system inside out, is comfortable with fluidity, and recognizes that the parts do not always fit into an integrated whole. The recent emphasis on ""core competencies"" and ""operating capabilities"" as keys to competitive advantage represents a radical shift away from the presumption that business leadership is primarily about strategic decisions. Corporate success, Sayles insists, now depends upon execution, implementation, and expertise. In the past managers presumed that work systems were programmed to be efficient; now astute managers recognize that extraordinary efforts are required to attain and maintain effective operations. Sayles shows with vivid case studies how middle managers with an in-depth understanding of the organization can resolve the inherent contradictions and ambiguities among design, sales, and manufacturing. He also shows that while many companies are instilling ""customer consciousness"" and ""quality consciousness"" as compartmentalized activities, effective management of work systems automatically leads to high performance in quality, efficiency, and service. By facilitating high performance, hands on working leaders can increase the sense of responsibility and motivation of subordinates. Finding solutions to inconsistencies and dilemmas in work systems forces managers to become real leaders. Checking the interfaces and making modifications where necessary -- managing on the boundaries -- are core competencies for the working leader.