METABOLIC ENGINEERING IS NOW AN ESTABLISHED DISCIPLINE as witnessed by the material assembled in this handbook and with a journal that is now more than 10 years old. With the impending change from chemical to biological feedstocks over the coming decades, this eld is taking on signicant socio-economic dimensions. Due to the unpredictability of the creative

process, it is always dicult to forecast the developments of scientic and engineering elds. However, it is important to try to look into the future and assess some of the impeding changes.