As effective organizational decision making is a major factor in a company's success, a coherent, comprehensive account of current available research on the core concepts of the decision support agenda is in high demand by academics and professionals alike. This encyclopedia presents a critical mass of research on the most up-to-date research on human and computer support of managerial decision making, including discussion on support of operational, tactical, and strategic decisions, human vs. computer system support structure, individual and group decision making, and multi-criteria decision making.