Optical polarimetry is a term we have recently adopted to denote any type of optical measurement where light polarization plays a key role, and where polarization itself is a carrier of information. It also refers to measurement of the state of polarization light which is emitted from various sources, over a wide range of wavelengths, or which is scattered by different objects. The sources may range from minute atomic samples to entire galaxies; and the objects may range from atoms, molecules, or micro-scopic particles to whole planets. Evidently this is a field of vast scope that would require several special issues to be represented adequately. Ellipsometry, a branch of optical polarimetry which deals with surface and thin-film characterization by polarized-light reflection, is alone the subject of a series of international conferences with proceedings published as special volumes of Surface Science.1 I n astronomy the measurement of polarization of light, both emitted and scattered, is finding broad application for deducing the microstructure of particles and the macrostructure of atmospheres.2 Other subspecialties of optical polarimetry have similarly expanded.