Today’s renewed interest in perfusion culture is due to an increased awareness of its advantages, some general improvement in equipment reliability, and a broadening of operational skills in the biomanufacturing industry. Some misperceptions persist, however, according to a 2011 review by Eric Langer (1). Our view here of the history of perfusion and fed-batch processes includes some discussion of technological process improvements and challenges that the bioprocess industry faces. A team of authors at Serono in Switzerland wrote…