The use of ultrasound for various diagnostic techniques in medicine continues to increase in popularity and complexity. It seems possible that the prediction of the National Science Foun­ dation that ultrasonic techniques may be used as frequently as X-ray techniques by the end of the decade may indeed be fulfilled. The annual scientific meeting of the American Institute of Ultra­ sound in Medicine is the only meeting held regularly on the North American continent and devoted solely to the diagnostic use of ultrasound. Under these circumstances it is not surprising to find that both the attendance at these meetings and the number of papers submitted for presentation, are increasing markedly each year. The papers presented at these meetings probably reflect the "state-of-the-Art" reasonably accurately. The Proceedings of these annual meetings are therefore a valuable record of the current state of ultrasonic diagnostic techniques in the U.S.A. Even though it is not possible to print in extenso every paper presented at the meeting, an attempt has been made with this volume, by increasing the length of the papers printed in abstract form, to enable the reader to obtain an overall view of current developments and research on this continent in all fields of ultrasonic medical diagnostic technology. Speed of publication is essential if this volume is to contain current information.