Architecture changed in the twentieth century. Long-held notions regarding permanence and the continuity of tradition were fractured by the trauma of World War I, and the calls for change that began in the nineteenth century eventually resulted in a fundamental, enduring shift in the way that buildings were conceived and executed. Building programs were increasingly closely designed to specific purposes that made adaptation and transformation difficult, and construction began to employ industrial, often experimental materials of uncertain quality or longevity.

In the 1980s, as modern structures themselves came increasingly to be viewed as part of history, architects and conservators began to confront firsthand the economic impracticality and, in some cases, the physically impossibility of their given task.

To address the increasingly dire, often insoluble problems of repairing or repurposing modern structures, a subdiscipline formed within the design and conservation communities to develop practical strategies and techniques within an evolving philosophical framework. With considerable hindsight this paper will speak, through case study and history, to the present, auspicious moment as one in which we may evaluate the wisdom and effectiveness of our efforts to date—and most intelligently plan for what the future might hold for the repair of yesterday’s frontier.