Over the past 50 years, all 50 States and over 500 municipalities have enacted laws to encourage or require the preservation of buildings and areas with historic or aesthetic importance. These nationwide legislative efforts have been precipitated by two concerns. The first is recognition that, in recent years, large numbers of historic structures, landmarks, and areas have been destroyed without adequate consideration of either the values represented therein or the possibility of preserving the destroyed properties for use in economically productive ways. The second is a widely shared belief that structures with special historic, cultural, or architectural significance enhance the quality of life for all. Not only do these buildings and their workmanship represent the lessons of the past and embody precious features of our heritage, they serve as examples of quality for today.