Welcome back to the Cost Corner, where we provide practical insight into the complex cost and pricing requirements that apply to Government contractors. The current topic is Federal Acquisition Regulation (FAR) Cost Principles applicable to contracts with commercial organizations. The previous four Cost Corner articles addressed the Cost Principles pertaining to the general criteria for determining the allowability of costs, direct and indirect costs, accounting for unallowable costs, and penalties for unallowable costs. This article begins coverage of FAR 31.205, Selected Costs, which includes forty-seven Cost Principles, each of which governs the allowability of a particular type of cost. The Cost Corner will not address all of the Cost Principles in FAR 31.205 but instead will focus on those that have, in our experience, generated the most significant questioned and disallowed costs.