The European radon programme M. Olast and J. Sinnaeve; natural environmental radioactivity with particular regard to radon gas and cosmic rays, W.W. Lowder; present and future radioprotection recommendations within the European Community with special regard to radon, G. Campos-Venuti; a review of experimental animal radon health effects data, F.T. Cross; review of the latest findings of population exposed to high background natural radioactivity, F. Steinhauser; the Italian National Survey on radon indoors run by several different regional laboratories - sampling strategy, realization and follow-up, F. Bochicchio et al; the regional survey of indoor radon in Friuli-Venezia Giulia, M.R. Malisan et al; radon monitoring in dwellings and in water in localized areas of Friuli Venezia-Giulia, A. Menin and A. Drigo; radon monitoring by passive detection, G. Torri; high level natural radiation areas with special regard to Ramsar, M. Sohrabi; realization of nuclear track filters and their applications to the study of environmental aerosol samplers, S-L Guo; grab sampling and continuous monitoring of radon and its progeny in air, G. Sciocchetti. (Part contents)