The field of optical coating is as large as the field of optics itself. Virtually every optical surface in every optical
instrument benefits from a coating that assures its correct optical properties. In this role optical coating is known as an
enabling technology because coatings enable the performance of optical systems. However there are also applications
where the optical coating itself plays the leading role by defining the technology. Anticounterfeiting devices, sensitive
detectors of miniscule amounts of material, certain display systems, are some examples. The field is huge and beyond
even this conference completely to cover. This account, therefore, picks just a few topics mostly of particular interest to
the author and follows some of the progress made in them over the years.