An important activity for an organization's leaders and managers is making decisions associated with problem-solving. Making decisions is a complex endeavor where choices are made from courses of action where resources are limited and in the presence of constraints. Written as a guide, this book offers a quantitative approach to decision-making. The process of decision-making is presented from a holistic point of view. This book offers a basic understanding of the issues and processes involved in decision-making by presenting the tools associated with problem analysis, tools that enable developing choices, as well as tools used to normalize judgment criteria achievement so that they are comparable across measures using different scales. Several solution methods for decision problems that have one evaluation criterion are explained first. Methods for problems with multiple criteria for evaluating alternate solutions are discussed as well. The multiple criteria methods include those that do not require any explicit preference or trade-off information from the decision-maker and those that do require the decision-maker's preference or trade-off information. The intended audience of the book includes technical and nontechnical professionals, managers, and supervisors at all levels, and engineering and business educators. The book would also be useful to undergraduate students, beginning graduate students, and recent graduates of professional programs, or in mathematics, computer science, natural sciences, and humanities.