The concepts, principles, and the general approach of systems cost analysis in support of cost-benefit studies are reviewed. The role of costs was considered both in individual system analysis and within the broader context of program analysis. This description of resource analysis was intended primarily for the users of cost estimates, as opposed to cost analysts. Users of cost estimates must face the critical task of judging cost estimates and evaluating their suitability and quality. The intent of this discussion was to improve the ability of those involved in the conduct of cost-benefit studies in non-defense agencies to appreciate the role of costing, to understand the limitations of cost analysis, and to establish adequate guidelines for the costing work done in support of these studies.