This essay is an excerpt of the chapter "Kontinuitet" from Harry Fett's memoirs Påx kulturvernets veier, published in 1944, written as a tribute to the centenary of the Society for the Preservation of Norwegian Ancient Monuments, an organization in which Fett played an important role for many years. The essay summarizes Fett's most important contribution to preservation theory: his argument that the cultural value of buildings was to be found in their continuous historical existence. Historic buildings rendered visible a binding continuity between the past and the present; thus Fett was skeptical about the trend of making historic buildings into museums as well as of modern reconstructions. He adopted the preservation theories of Georg Dehio and Aloïs Riegl, summarized in the slogan "conservation, not restoration." Fett sought to preserve historic buildings as parts of living societies and to carefully adapt their use to modern needs. One of his standpoints—radical for its time—was that entire interiors and urban or rural environments should be preserved instead of individual objects and buildings. With his colleagues in Denmark and Sweden, Fett took important steps toward the realization of this ideal through administration and legislation as well as through his involvement in a number of individual cases in Norway. His motivation was a conviction that the loss of historic buildings and environments inevitably implies loss of identity and thus of humanity and moral values.