IRAS, the infra-red astronomical satellite, is proving to be one of the most successful of all space missions. Already it has carried out an all-sky survey in infra-red, discovering hundreds of thousands of new infra-red sources ranging from very young stars out to remote quasars. Patrick Moore talks about these striking developments with Dr Jim Emerson of Queen Mary College, a British member of the IRAS team which also includes specialists from Holland and the United States.