Techniques such as Raman, infrared, fluorescence, and even nonlinear spectroscopies have recently grown in resolution and possibilities thanks to the use of nanostructured surfaces. Excitation of localized surface plasmon (LSP) and/or the use of specific shapes of nanostructures have made it possible to gain an incredible sensitivity in these spectroscopies. Unlike other books in the market, which mainly focus on surface-enhanced Raman spectroscopy (SERS) and plasmonics, the aim of this book is to provide the reader with a detailed overview of enhanced spectroscopies. It introduces plasmon and electromagnetic effects arising in metallic nanostructures, and reviews the above spectroscopies, enhanced by the presence of either a nanostructure or a tip. It reviews the theoretical basis of each technique, describes experimental procedures, and suggests some applications.