Autotrophic microorganisms have the ability to convert light into chemical energy and to use this energy to bind carbon dioxide. This adds to the mass balance of the re¬sources available for our society. With the depletion of fossil resources, and limited increase of the agricultural production, autotrophy has the potential to provide an ever-growing human population with chemical products. From a synthetic viewpoint, autotrophy is a very promising approach for the supply of chemical energy for synthetic reactions. Yet, on the way to a wide industrial application, several technical challenges must be overcome. The book outlines the most important autotrophic microorganisms and strategies for their biotechnological utilization. It gives an overview on enabling technologies such as engineering of metabolic enzymes, molecular biology tools for autotrophic microorganisms and new bioreactors to are expected to accelerate the progress in this field.