The unique catalytic properties of enzymes and the numerous techniques for immobilization of enzymes and cells continue to maintain a high degree of practical and scientific interest in this area called Enzyme Engineering. This fourth International Enzyme Engineering Confer­ ence was the first to be held outside of the United States. Europe was chosen as the site primarily to en­ able greater participation by investigators from that continent. The Engineering Foundation of New York, which was the principal sponsor of the first three conferences, was most fortunate in having the DECHEMA (Deutsche Gesell­ schaft fur chemisches Apparatewesen e. V.) of Frankfurt (Main), F. R. Germany as the cosponsor for this fourth conference. The success of the conference also was due in large part to the generous financial support, especially by the government of the Federal Republic of Germany, as well as by European enzyme and chemical companies. The fourth conference, held September 25-30, 1977 at Bad Neuenahr, Federal Republic of Germany was certainly successful, with 240 participants from 23 countries, repre­ senting many academic disciplines and occupational special­ ties. At this conference special emphasis was placed on the immobilization of whole cells and organelles, medical applications of immobilized enzymes and organelles, and the industrial status and future for immobilized biological materials.