The Information Theory (IT) is one of the youngest branches of the applied probability theory, in which the probability ideas have been introduced into the field of communication, control, and data processing. It has originated from the needs of practice, to create a theoretical model for the transmission of information, and evolved into an important chapter of the general theory of probability. An understanding of the distribution of information in molecules and its displacements accompanying chemical reactions, which involve the bond-forming and/or bond-breaking processes, is touched on in this book and provides an alternative perspective on molecular electronic structure. An insight into the entropic origins of chemical bonds and their coupling in chemical phenomena is central to many branches of chemistry.