At the end of the 20th century, a tremendous progress was made in biotechnology in its widest sense. This progress was largely possible as a result of joint efforts of top academic researchers in both pure fundamental sciences and applied research. The surplus value of such interdisciplinary approaches was clearly highlighted during the 9th European Congress on Biotechnology that was held in Brussels, Belgium (11-15 July, 1999). The present volume in the Focus on Biotechnology series, entiteld Physics and Chemistry Basis for Biotechnology contains selected presentations from this meeting, A collection of experts has made serious efforts to present some of the latest developments in various scientific fields and to unveil prospective evolutions on the threshold of the new millenium. In all contributions the emphasis is on emerging new areas of research in which physicochemical principles form the foundation. In reading the different chapters, it appears that more than ever significant advances in biotechnology very often depend on breakthroughs in the biotechnology itself (e.g.