This special volume "Tools and Applications of Biochemical Engineering Science" is dedicated to Professor Wolf-Dieter Deckwer on the occasion of his 60th bir- day. It was a great pleasure for me to act together with Professor Karl Schtigerl as volume editor and to present here a collection of 11 outstanding review articles written mainly by former students, associates, colleagues and friends of Wolf- Dieter Deckwer. The title of this special volume well reflects the research interests and sci- tific pursuit of Wolf-Dieter Deckwer during his more than 20 years’ work in the area of biochemical engineering, particularly during the last 15 years when he was the head of the Biochemical Engineering Division of GBF (German Nat- nal Research Center for Biotechnology). He has decisively pushed the devel- ment not only of "software tools" ranging from analytical means and mathe- tical models for monitoring and understanding cellular processes to gene expression systems for designing microorganisms, but also of "hardware tools" such as computer control systems, bioreaction and separation devices for eff- tively producing a variety of bioproducts on semi-production scale. New developments in some of these important tools in biochemical engineering are reviewed in articles included in this volume. Wolf-Dieter Deckwer was among the leading biochemical engineers who timely pointed out the necessity of applying these tools in an integrated manner for bioprocess development. By establishing "Integrated Bioprocess Development" as one of the GBF main - search topics as early as 1990 he also actively promoted this idea.