From the Preface The world of spectroscopy began its development in the second half of the XX century and has been constantly evolving ever since. From being a set of specialized techniques available only to a few, spectroscopy -in its many facets- has now become a tool chest in demand by engineers and scientists of different backgrounds. Unfortunately, the physics concepts underlying the spectroscopic techniques remain in the field of physics and most users -being from backgrounds other than physics- learn to use commercial spectroscopy devices without ever learning much about their...