During the 50s and 60s the theories of the principal members of the Frankfurt School-Max Horkheimer. . W. Adorno and Herbert Marcuse - inspired the revival of radical thinking in Germany and the formation of a German New Left. In assessing the Frankfurt School's Critical Theory and its impact Heinz Lubasz of Essex University talks to Marcuse, Horkheimer's successor Professor Alfred Schmidt , the philosopher Karl Popper , the sociologist Ralf Dahrendorf and former student leader Rudi Dutschke. Producer ADRIAN JOHNSON