This volume deals with "Microbial Production of L-Amino Acids" and presents five comprehensive, expert and actual review articles on the modern production of Amino Acids by application of biotechnologically optimized microorganisms. This includes not only the modern techniques of enzyme, metabolic and transport engineering but also sophisticated analytical methods like metabolic flux analysis and subsequent pathway modeling. A general review about industrial processes of Amino Acid production provides a comprehensive overview about recent strain development as well as fermentation technologies. It was our special interest to focus the other articles on the most important and best selling amino acids on the world market i.e. L-Glutamate, L-Lysine and L-Threonine. The authors of this special volume have contributed significantly to the progress of Amino Acid biotechnology in the last decades and earn our special gratitude and admiration for their expert review articles.