This book describes recent progress in the mechanistic studies and applications of surface-enhanced Raman scattering (SERS) and tip-enhanced Raman scattering (TERS). In this book, various novel techniques in SERS and TERS such as UV resonance TERS, electrochemical TERS, and three-dimensional SERS imaging are outlined. A number of new applications of SERS and TERS such as those to photonics, nanotechnology, microfluidics, and medical diagnosis along with future perspectives are also discussed. Finally, the applications of new data analysis, models, and machine learning in SERS and TERS studies are reviewed. The novelty of this book is the forming of a new bridge between the theory and applications. Also, the importance of chemical mechanism and that of semiconductor-enhanced Raman scattering is emphasized. The main audiences are researchers in academia, research institutes, companies, and graduate students looking for a comprehensive book on the latest studies of SERS and TERS.