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.This proceedings volume, featuring contributions from many of the key players in the field, serves as a definitive source of information on this subject, 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 including fifth forces and dark energy.