Photothermal Investigations of Solids and Fluids discusses photothermal optical diagnostic techniques in the study of solids and fluids, which involve areas of photothermal spectroscopy, imaging, and velocimetry. This book explores the development of lasers as powerful and convenient sources of localized energy. Organized into 10 chapters, this monograph begins with an overview of photothermal spectroscopy as the field in which the nature of matter is probed using optical excitation of a medium and optical probing of the thermal energy that results from this excitation. This book then provides the reader with a link between the physics applicable to the photothermal experiments and the methodology involved in such investigation. Other chapters examine the experimental photothermal detectors that are constructed for use in most forms of chromatography and electrophoresis. The final chapter deals with several promising spectroscopies, including photothermal interferometry, photothermal modulation of Mie scattering, and photophoretic spectroscopy. Graduate students, professors, and research scientists will find this monograph extremely useful.