An Advanced Study Institute on Ultrasonics in Medical Diagnosis was held in Milan, Italy, from 10 to 15 June 1974. This ASI was of a short five-day duration and limited to cardiac diagnosis by ultra­ sound only. Since that time, the field of diagnostic imaging in medicine has literally exploded with new and improved means of medical diagnosis such as computed tomography, microwaves, nuclear magnetic resonance and other sophisticated techniques. These developments have enabled medical practitioners to make diagnoses with a minimum of danger to the patient, and a maximum of accuracy never before possible, and represent a multi-quantum advance over the early state-of-the-art presented at the 1974 ASI. Since then, several meetings have taken place on these individual topics to bring together experts who presented their latest research results, but none have discussed the entire field of diagnostic imaging in medicine in one meeting nor have they had the teaching character of an Advanced Study Institute. The art and science of medicine have been altered repeatedly during the eight year interval since the last ASI. Today's clinician must be part technologist and must be enough of an investigator to understand and appreciate the scientific method. The current complex advances in instrumentation and pharmacology have had a marked effect on how medicine is practiced. There was, therefore, an urgent need to bring the entire field of imaging in medicine to one teaching podium where the many advances of the last six or seven years could be reviewed.