San Francisco, California, 1-3 May 2001

Acoustic interference phenomena in the ocean can be described by a robust "waveguide" invariant. These proceedings of the first U.S. workshop on this topic record in English the findings of Russian scientists, who for many years have worked on all aspects of the subject, and American scientists, who have recently worked in this area emphasizing the acoustics of shallow water regions and signal processing applications. Theory, experimental methods, acoustic fluctuations, and array processing emerge as the major research issues.