The book covers the theories and physics of advanced new optical measuring methods and problems of experimental performance, recent achievements in the basic interferometric methods holography, speckle-interferometry, shearography as well as linear/non-linear photoelasticity and photoviscoelasticity, Moire- and grid-techniques. It deals with theory and application of digital image processing, methods of data recording, data processing and -visualisation, with mathematical/numerical procedures for final evaluation of digitised measured data and the principle of hybrid techniques. It introduces into the new perceptions of methods in experimental solid mechanics and it should encourage scientists to deal intensively with the theories for further developments, and enables practitioners, to understand theory and physics of the new achievements at least and to apply the methods in research als well as in developments in practice.