Metabolic engineering is a rapidly evolving field that is being applied for the optimization of many different industrial processes. In this issue of Advances in Biochemical Engineering/Biotechnology, developments in different areas of metabolic engineering are reviewed. The contributions discuss the application of metabolic engineering in the improvement of yield and productivity - illustrated by amino acid production and the production of novel compounds - in the production of polyketides and extension of the substrate range - and in the engineering of S. cerevisiae for xylose metabolism, and the improvement of a complex biotransformation process.With contributions by numerous expertsMetabolic engineering is a rapidly evolving field that is being applied for the optimization of many different industrial processes. In this issue of Advances in Biochemical Engineering/Biotechnology, developments in different areas of metabolic engineering are reviewed. The contributions discuss the application of metabolic engineering in the improvement of yield and productivity - illustrated by amino acid production and the production of novel compounds - in the production of polyketides and extension of the substrate range - and in the engineering of S. cerevisiae for xylose metabolism, and the improvement of a complex biotransformation process.After a Decade of Progress, an Expanded Role for Metabolic Engineering.- Metabolic Engineering for L-Lysine Production by Corynebacterium glutamicum.- Process Development and Metabolic Engineering for the Overproduction of Natural and Unnatural Polyketides.- Metabolic Engineering of Saccharomyces cerevisiae for Xylose Utilization.- Metabolic Engineering of Indene Bioconversion in Rhodococcus sp..- Metabolic Engineering of the Morphology of Aspergillus.- Evolutionary Engineering of Industrially Important Microbial Phenotypes.Thl£¾