Proceedings of the Ninth Conference on Quantum Field Theory Under the Influence of External Conditions (QFEXT09) Devoted to the Centenary of H.B.G. Casimir, University of Oklahoma, USA, 21-25 September 2009

QFEXT is the leading international conference held every two years, highlighting progress in quantum vacuum energy phenomena, the Casimir effect, and related topics, both experimentally and theoretically. Most of the key players in the field are expected to be present. Thus the proceedings will be the definitive source of information on this field, which is playing an increasingly important role in nanotechnology and in understanding fundamental issues in physics such as renormalization and in the search for new physics such as fifth forces and dark energy. Proceedings of previous conferences in this series have been important, and like the conferences they summarize, have led to major progress in the two subsequent years. This is because, the fundamental aspects of quantum field theory; applications of all branches of physics, chemistry, nanoscience, and astrophysics; mathematical and experimental techniques described have wide applications and all leading groups and scientists working in this field will be represented.