Comprehending radiation risk is a challenge for society. In order to explore the subject an IAEA conference was held in 1994 . The plenary programme consisted of three distinct elements: three technical days, a media day and a decision-makers' day. Prior to the conference backgroud papers were prepared to serve as a basis for the technical discussions. This volume contains the two background papers prepared for the conference by the IPSN and the text of the poster presentation.