The present book deals with the quantitative measures of information so as to provide their applications in different fields of Operations Research and Statistics. It is worth mentioning that the two basic concepts, viz, entropy and divergence which are closely related to each other have been investigated and applied to various disciplines of Mathematical Sciences. Another idea providing a holistic view of problems comes under the domain of Jaynes "Maximum Entropy Principle" which deals with the problems of obtaining the most unbiased probability distributions under a set of specified constraints. The contents of the book provide a detailed study of the maximum entropy principle. I sincerely hope that the present volume of the book will be useful to all those interested in the mathematical models and their optimization. Moreover, it will be a source of inspiration and encouragement to all research scholars and teachers to discourse the subject for the discovery of new insights.