Professor Ramakrishnan has made crucial contributions to our understanding of condensed many body systems. His pioneering work started two major areas of activity. These are: the liquid - solid transition as well as related phenomena in dense classical systems, and the onset of electron localization in disordered systems. He has also made many significant contributions to their growth. In a third area, namely mixed valence in rare-earth metals, his work on the inverse orbital degeneracy expansion has had a major effect on the field