City plans are grounded in analysis of local condition and contain a vision of an urban future that the citizens, local elected officials, planning staff and consultants consider desirable. Urban plans vary greatly in approach, content, sophistication, comprehensiveness, time frame and format. In the first half of the twentieth century, urban planning was elitist and paid little attention to implementation. Planning theory was focused on how to create stable cities, geared to a static world and based on a similar system of rules. During this period the planners were free from political interference. Planners actually work with neighborhood residents, local elected officials, interest groups and private developers. Planners negotiate, mediate, resolve conflicts and serve like diplomats. We must accept and study an approach to urban planning that recognizes that different groups compete in the planning process. What makes urban planning so fascinating is the variety of issues planning theory and practice must confront. Issues of aesthetics, design, economic feasibility, decision-making theory, conflict resolution and sustainability are just some of the core concerns which planning must confront in the twenty-first century.