The methodology used is to first expose the students to the fundamental concepts through a numerical illustration and then explain the underlying theory wherever required. The inclusion of a case study in each chapter of this second edition has made learning easier and more effective. The book introduces the readers to various models of operations research, such as the transportation model, the assignment model, the inventory model, the queueing theory and the integer programming model. The various techniques to solve OR problems faced by managers are also discussed. Separate chapters are devoted to linear programming, dynamic programming and quadratic programming which greatly help in the decision-making process.