This report describes the underlying motivation, characteristics, and possible applications of the VISION (Visibility of Support Options) Assessment System, a decision support system designed to improve the ability of Army logisticians to address three issues that are fundamental to Class IX (spare parts) sustainment planning: (1) assessing whether the logistics system can support operational needs and objectives throughout the course of a planned conflict, (2) determining where and when problems are likely to emerge and how serious they are likely to be, and (3) identifying what can be done beforehand to avoid or mitigate those potential problems. Among the potential uses of the VISION Assessment System, the authors identify (1) assessing and improving the supportability of existing operation plans (OPLANs), (2) evaluating and choosing among alternative courses of action during OPLAN development, (3) identifying effective peacetime strategies for overcoming potential wartime problems, (4) examining new concepts and establishing new doctrine, (5) exploring cost-reduction strategies and weighing tradeoffs among different resources, and (6) reporting unit sustainability.