Nine years ago, in 1967, a conference on spallation nuclear reactions and their applications in astrophysics was held at the University of Pennsylvania. I Since that time, a number of devel- opments have given renewed impetus to the study of spallation reactions. Among these are the successful acceleration of high- energy heavy ions in the laboratory and their potential use in cancer radiotherapy, the availability of returned lunar rocks containing records of past cosmic-ray irradiation, and the devel- opment of the theory that the spallation of interstellar matter is responsible for much of...