A year after the passing of Don Helmberger,it is remarkable how memories of interactions with him over my entire professional career continue to spark affection and admiration.I arrived at Caltech in the summer of 1978 having had typically little exposure to seismology as an undergraduate.One of my academic advisors during my undergraduate program in Geomechanics(a joint program between Geology and Mechanical Engineering at the University of Rochester)was Geoff Davies,who had received his Ph.D.at Caltech working in mineral physics.