The revised edition of this book has been written primarily for students who may only possess elementary mathematical knowledge but want to understand the concepts and techniques in the field 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. The opening chapter of the book presents an overview of O.R. followed by a chapter wherein problem formulation and modeling have been dealt with in full details. The third chapter makes lucid exposure of ‘Random Variables O.R. techniques (including Investment Decisions: Analysis of Risk and Statistical Quality Control Techniques) have been described and illustrated in chapters four to eighteen. 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 skillfully 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 M.M.A., of Com., C.A., I.C.W.A. and MBA.