Cities and towns are among humanity's largest and most complex achievements. The buildings, public works, plazas and parks of even a small town embody substantial amounts of capital, energy, natural resources, history and aspirations. Cities are among our greatest creations, yet typically no single individual creates them. Rather they arise from the dialog between multiple designers, clients, regulators, citizens, critics and users. Sometimes the cities and towns that emerge are glorious places. Too frequently they have only fragments of greatness or are soul-deadening and environmentally unhealthy. Just as private doctors have responsibilities to their individual patients and for public health, project designers are accountable to their clients and for a set of public goods such as environmental stewardship, fostering civil society, and inspiring joy. Urban Composition introduces essential ways in which the architects, planners, artists and engineers of individual projects can fulfil their public trust to help make great urban places.