Raman spectroscopy : an intensity approach Raman effect Normal mode vibration The elucidation of bond polarizabilities The Raman virtual states More applications The extension to Raman optical activity More applications on ROA Intra molecular enantiomerism A unified classical theory for ROA and VCD This book summarizes the highlights of our work on the bond polarizability approach to the intensity analysis. The topics covered include surface enhanced Raman scattering Raman excited virtual states and Raman optical activity (ROA). The first chapter briefly introduces the Raman effect in a succinct but clear way. Chapter 2 deals with the normal mode analysis. This is a basic tool for our work. Chapter 3 introduces our proposed algorithm for the Raman intensity analysis. Chapter 4 heavily introduces the physical picture of Raman virtual states. Chapter 5 offers details so that the readers can have a comprehensive idea of Raman virtual states. Chapter 6 demonstrates how this bond polarizability algorithm is extended to ROA intensity analysis. Chapters 7 and 8 offer details on ROA showing many findings on ROA mechanism that were not known or neglected before. Chapter 9 introduces our proposed classical treatment on ROA which as combined with the results from the bond polarizability analysis leads to a comprehensive physical picture for the Raman effect. In particular this classical treatment unifies ROA and VCD (vibrational circular dichroism) on equal footing. In each section Comments summarize the key ideas and their evaluation. This will help the readers to capture the core ideas of the presentations