[en] The Proceedings contain 20 contributions dealing with diverse aspects of the radon problem. Information is presented on the occurrence of radon on the territory of Czechoslovakia, and on natural radioactivity of rocks. The majority of contributions concentrate on ways of radon measurement, on determination of the radon content of building materials and on radon propagation through buildings. Various technologies for removing radon from homes and for preventing radon leaks are described and assessed. The effect of radon on human health is also dealt with. (M.D.). 16 tabs., 34 figs., 39 refs