Following the rapid developments in the UV-B measurement techniques and the rapidly growing research in the field in the late 80's and early 90's, we organized a large gathering of distinguished experts in a NATO Advanced Study Institute, held in Halkidiki, Greece on October, 2-11. 1995. The Institute was organized so as to include state of the art lectures on most aspects of solar ultraviolet radiation and its effects. This was achieved by extended lectures and discussions given in five sessions by 27 lecturers and a demonstration of filed measurements and calibration techniques at the end of the Institute. The ASI began with the sun and fundamentals on solar radiative emissions and their variability in time and continued with the interaction of solar Ultraviolet with the atmosphere through the complex scattering processes and photochemical reactions involved. Particular emphasis was given to changes in atmospheric composition imposed by different manifestations of the solar activity cycle. as well as on the modelling of radiative transfer through the atmosphere and the ocean under variable environmental conditions. Overviews on the ozone issue. its monitoring and variability were extensively discussed with emphasis on the observed acceleration of ozone decline in the early 90's. This acceleration had as a consequence, significant increases in UV-B radiation observed at a few world-wide distributed stations.

Extraterrestrial Solar Irradiance in the Near and Medium UV Ranges.- Stratospheric Ozone Depletion and UV-B Changes.- Theoretical Estimation of Biologically Effective UV Radiation at the Earth's Surface.- Transfer of Ultraviolet Light in the Atmosphere and Ocean: A Tutorial Review.- Atmospheric Ultraviolet Radiation Scattering and Absorption.- Modeling of Stratospheric Ozone.- Satellite Mapping of Solar Ultraviolet Radiation at the Earth's Surface.- Spectroradiometer Calibration Methods and Techniques.- Factors Influencing the Transmission of Solar Ultraviolet Irradiance Through the Earth's Atmosphere.- Underwater Spectral Measurements.- Methods to Derive Geographical Differences of UV Irradiances.- Spectrometers: Operational Errors and Uncertainties.- Broad-Band Detectors for UV-Measurements.- Monitoring Personal Exposure to Solar Ultraviolet Radiation.- Effects of UV-B Radiation on Terrestrial Plants.- Impact on Marine Ecosystems.- Solar UV Effects in Algal Assemblages of the Caribbean and the Mediterranean Seas.- Ozone and UV Public Awareness Programs.- Observed Dependencies of Atmospheric UV Radiation & Trends.- Current Status of UV Measurements.- UV Spectro-Radiometry in the Network for the Detection of Stratospheric Change (NDSC).- Solar UV and the WMO Global Atmosphere Watch System.- The Role of Ancillary Measurements.- Global Ozone Change and Possible Climate Implications.