JENS RASMUSSEN was a research professor of cognitive systems engineering at Ris National Laboratory and the Technical University of Copenhagen, following 25 years as the head of the Electronics Department at Ris National Laboratory. Since 1962, he has conducted research in the areas of reliability and risk factors, human reliability, work domain taxonomy, human-machine interaction, and ecological information systems design. A distinguished leader in these fields, he has chaired a number of groups of international experts appointed to assess risk and human-machine interaction in nuclear and other hazardous industries. He is now a consultant in cognitive systems engineering and risk management.