The book covers the standard models and techniques used in decision making in organizations. The main emphasis of the book is on modeling business-related scenarios and the generation of decision alternatives. Fully solved examples from many areas are used to illustrate the main concepts without getting bogged down in technical details. The book presents an approach to operations research that is heavily based on modeling and makes extensive use of sensitivity analyses. It is a result of many years of combined teaching experience of the authors. The second edition adds new material on multi-criteria optimization, postman problems, Lagrangian relaxation, cutting planes, machine scheduling, and Markov chains. Support material is found on a free website and includes some algorithms, additional fully solved problems and slides for instructors.