Volume XXVIII contains five review articles covering the following areas - digital holography, a field that has found useful applications in connection with data processing and data storage, for 3-d displays and in providing new types of optical components, for example, holographic gratings; - basic investigations concerned with new technologies that may lead to better optical communication systems and improved limits of measurement than are expected from the traditional interpretation of quantum-mechanical measurement theory; - a review of our current understanding of quantum coherence properties of stimulated Raman scattering; - an account of techniques developed in recent years in the field of interferometry, for improvements of high precision measurements; - the fascinating phenomenon of quantum jumps, which were introduced in the theory of atomic spectra by Niels Bohr in 1913.