The first meeting on biosonar that I had the opportunity to attend was held in 1978 on the Island of Jersey in the English Channel. That meeting, organized by Professor R.G. Busne1 and Dr. Jim Fish, was my introduction to an exciting and varied group of hard-working and dedicated scientists studying animal echolocation. They are, by nature, a very diverse group. They tend to publish in different journals and rarely interact despite the fact that they all work on echolocation. When they do interact as a group, as they did in Frascati Italy in 1966, in Jersey i~ 1978, and during the meeting reported in this volume, the meetings are intense, interesting, and exciting. This volume is a composition of a series of contributed papers written to foster an interdisciplinary understanding of the echolocation systems of animals. The echolocation pulse production studies in bats and dolphins have recently been concentrated on the ontogeny of infant pulses, other studies, with three-dimensional computer graphics and x-ray computed tomography, have concentrated on finally resolving the old controversy concerning the site of dolphin echolocation click production. Much has been accomplished on the analysis of bat neural structure and function. The intense effort directed toward understanding the structure, connections, and functional properties of parallel auditory pathways and the parallel and hierarchical processing of information by the mustached bat, has lead to dramatic breakthroughs in understanding brain function.