Research by the author of the book A.A. Verbovetsky possibilities of optical holography for building digital holographic storage devices (GZU) of large capacity. Experimental installations, techniques and methods for obtaining holograms with discrete digital information developed by the author are described; studies of their properties and various factors affecting both recording and reading digital information from them; encoding methods, digital information and other methods which increase parameters of both individual microholograms and arrays thereof when forming a digital GZU medium.