This volume contains the Proceedings of the Fifth International Symposium on Acoustical Holograhy and Imaging, held in Palo Alto, California, on July 18-20, 1973. The title of this Symposium differed from that of the previous four by the addition of the word "Imaging," reflecting an increase in emphasis on nonholographic methods of acoustical visualization. For convenience, no change has been made in the title of this published series. The 42 Symposium papers cover a wide range of theoreti­ cal and applied topics, and effectively define the state-of­ the-art in this rapidly developing field. Many of them relate to applications of acoustic visualization in such diverse fields as nondestructive testing, medical diagnosis, microscopy, underwater viewing, and seismic mapping. The papers presented at the Symposium were selected with considerable assistance from the Program Committee. The Editor wishes to thank the following persons for serving as members of this committee: P. Alais, University of Paris, France; B. A. Auld, Stanford University; D. R. Holbrooke, Children's Hospital of San Francisco; A. Korpel, Zenith Radio Corporation; J. L. Kreuzer, Perkin Elmer Corporation; A. F. Metherell, Actron Industries, Inc.; R. K. Mueller, Bendix Research Laboratories; B. Saltzer, u.S. Naval Under­ sea Research and Development Center; F. L. Thurstone, Duke University; and G. Wade, University of California, Santa Barbara.