This volume contains a well balanced combination of theoretical and experimental state-of-the-art results of Active Flow Control. It combines new developments in actuator technology, sensing, robust and optimal open- and closed-loop control and model reduction for control. Numerical and experimental applications are considered from aeronautics, turbo-machinery and combustors. The contributions to this book were presented at the conference Active Flow Control 2006, held September 27-29, 2006, at the Technische Universität Berlin, Germany. The conference was organized by the Collaborative Research Center SFB 557 ‘Control of complex turbulent shear flows’, which is funded by the DFG (German Research Foundation).