The revised edition of this book has been written primarily for students who want to understand the concepts and techniques of Operations Research. As such, all important O.R. techniques have been described and illustrated in a lucid and easy-to-follow style. The helping statistical tools, especially the random variable and probability distributions, have also been taken care of in the present volume. The objective kept in view throughout has been to introduce basic O.R. concepts along with their applications in the context of real life industrial and business situations. At the end, three appendices have been devoted toward the salient features of Markov Processes, Work Study and Exponential Smoothing respectively, so often talked about in the context of O.R. The distinct feature of the book is that mathematical complexities have been skilfully kept away to the extent possible for a quick and easy grasp of the techniques by all concerned. The book is intended to be a text-book primarily for the students MMA, of Com., CA, ICWA and MBA.