It was clear during the decade before 1966 that “in any appraisal of [Park] Service work historic preservation looms large, and it is plainly growing more rapidly than natural area preservation.” Part of the Mission 66 challenge was that the agency “should reassert” its national leadership role in historic preservation as part of “contemporary conservation.” The agency needed to “strengthen its authorized historical services and activities” because these external programs were “among our best spokesmen for historic preservation.” At the same time, internally, the Park Service leadership considered “some liberalization of existing practice” by altering parts of its restoration policy to embrace the adaptive use of historic properties.6