The top engineering achievements of the 20th century, from the automobile and airplane to telephone, radio, TV and computer, all constitute “complex technical systems,” says Tom Magnanti. It is certain that the next century’s top engineering challenges, such as “reconciling the inevitable growth in world-wide energy demand with potential environmental costs,” will involve complex solutions, too. Will engineering systems (ES) as a discipline play a critical role in educating engineers to respond successfully to these challenges? Magnanti takes up the slippery issue of what constitutes ES as a field. He examines earlier MIT curricula, such as Systems Design and Management, and the 4M Conceptual model (Mine, Model, Manipulate, Measure), for ways to think about his topic. “Is ES a single discipline the way sociology and psychology are?,” he ponders. He applies different architectural constructs to engineering systems: Should ES be viewed as an intersection of engineering, management and social sciences and thus a subset of each; or as borrowing components from technology, economics, human resources, design, and thus comprising “all of engineering plus everything else.” Networking may prove central to all ES work, Magnanti says, whether ES is a single discipline or a “field that has a core focus … and draws upon multiple disciplines.