In this new edition the authors have added new material and included more applications in all the chapters, revising the explanation and presentation of some topics, increasing the number of exercises, and achieving a greater independence of chapters as far as possible. Examples of new material include a complete new chapter on decision analysis; the computer solution of linear programming problems, the use of sensitivity analysis output; the addition of minimal spanning tree; a new section on goal programming - theory, algorithm and applications; the addition of network queues; a discussion of microcomputer based simulation languages and their applications; and the inclusion of second order gradient based optimization techniques.