This is a description of the development of active and passive thin films on glass at Schott. Design strategies, the use of conventional and newly-developed production technologies, and the application of characterization methods for the structure of thin films and their properties are reported. The work illustrates how the best film materials and deposition and processing parameters may be selected. The topics covered include flip-flop layers, wave-guiding films, Rugate filters and gradient devices, optical transducers, coatings, and mirrors.