The present book expedites the concept of Non- additive entropies especially Kapur's and Tsalli's entropies in communication systems. It acquaints the readers not only with the related mathematical modeling but also discuss their basic properties applicable to large domain in communication systems. Moreover, book provides deeper insight of the concepts like composability, stability and time-frequency representation of non-additive entropies. In the present era, the interdisciplinary approach towards the concepts is increasing and integrated so as to boost research. Therefore, the present efforts are to bring out the work can be useful to disciplines of theoretical sciences.