This book will focus on decisions support systems (DSS) ranging from traditional decision theories and analysis to advanced DSS using Game Theory, Emerging Optimization, and advanced mathematical modeling and simulation (M&S) Techniques. The book will be organized into five topics, including Topics 1, 2, 3, 4, and 5. Topic 1 will focus on traditional and advanced decision theories and analyses. Topic 2 will emphasize DSS under uncertainty and/or risk. Topic 3 will thematize DSS and cognitive technologies. Topic 4 will focus on decision analytics and DSS using machine learning and artificial intelligence, and advanced mathematical M&S techniques. Finally, Topic 5 is on decision support tools and applications. The book is planned for professional engineers, scientists, mathematicians, and researchers working in sciences, technologies, engineering, and mathematics (STEM) fields. Hence, its objective is to collect and present chapters related to DSS theories, analyses, tools, and applications that contained open problems with technical relevance to STEM fields.