This chapter explores the applications of various acoustic techniques that were discussed during the trip. The WTEC team saw many systems and research interests in the United Kingdom, France, and Russia. This discussion is not meant to represent all such applications being undertaken in all of the countries referenced. Many more are undoubtedly underway. The applications mentioned, however, do give a sense of the relative breadth and level of technology being worked within each of those countries. This summary of activities is considered to be a snapshot and suffers from limited technical depth and scope.