The working group took its objective to be the formulation of a set of research and development recommendations for assessment of aging energy systems. The material discussed in every session at this workshop has relevance to the assessment of characteristics such as the current state of these facilities or their components. Indeed many of the items we cite will appear elsewhere as well. The focus we have maintained, however, is assessment for the direct purpose of decision making. The decisions may have to do with increasing inspection, monitoring or analysis, or with repair, or even with closure and replacement. The assessment may be the risk assessment of an individual structure or the problem may be that of designing a cost-efficient inventory of the status of a large “fleet” of facilities.