Flow Control and Optimization is increasingly incorporated in the design of engineering devices ranging from aircraft and space vehicles to micro?uidic devices. Research in this ?eld aims to integrate knowledge in ?ow physics with theoretical advances and novel experimental capabilities and engineering devices capable of materializing advanced design concepts. In turn controlled ?ow phenomena exhibit a new arrays of physics and open frontiers for further interdisciplinary research in ?uid mechanics and all the engineering domains that it a?ects. This collection of papers in ?ow control, showcases representatives lines of work in the area of ?ow control demonstrating the interdisciplinary character and high scienti?c merit of this ?eld. The authors of these articles are among the pioneering researchers in this ?eld and continue to explore the frontiers in ?ow control and optimization. We hope that this volume, while largely representing work by the authors prior to 2004, contributes in providing an authoritative report on this rapidly changing ?eld.