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.