It would be superfluous to stress the importance of electronic .spectroscopy in structural or analytic research. It has now become a matter of routine to record the ultra-violet or visible spectra of compounds for purposes of identification or structure elucidation. The spectrophotonletric methods of analysis have replaced the conventional methods in ever so rnany instances. The number of-publications in the different branches of chemistry, reporting data on or making use of electronic spectroscopy, is ever-increasing and it would be impossible to review the field completely. In this book, I have tried to introduce the basic concepts of electronic spectroscopy and to present its applications in analytical, structural and physico-chemical problems. As far as possible, the rnateripl has been selected to illustrate the basic: principles of modern theories in chemistry. While surveying the data on organic molecules, several empirical generalizations have been discussed. lVlany of the more recent developments like tIle far ultra-violet spectra of organic molecules, fluorescence spectra, charge transfer spectra, ligand field theory, optical rotatory dispersion etc., have been briefly discussed in the latter part of the book. All through the discussion, the recent notations of electronic transitions have been used, although the other commonly encountered notations have also been mentioned. I shall be most gratified if this book can be of help to chemists in using electronic spectroscopy more effectively in research or routine work.