Book excerpt: This volume contains the lectures presented at the Workshop on QCD Vacuum Structure and Its Applications, held in Paris, France, in June 1992. The structure of the vacuum state of quantum chromodynamics is one of the major unsolved problems in strong interaction physics. Although considerable progress has been made in the last decade in understanding various aspects of QCD vacuum structure, a unified picture is still elusive. This volume covers recent advances in the major fields of relevance to the problem of the QCD vacuum, such as quark confinement, chiral symmetry breaking, nonperturbative approaches, and QCD vacuum phenomenology. It provides the first comprehensive presentation of this subject, and will be valuable tool for theorists interested in nonperturbative QCD, hadronic structure, and relativistic nuclear physics.