Donald Vincent Helmberger,Ph.D.and Smits Family Professor of Geophysics Emeritus at Caltech(Figure 1),one of the primary founders of seismic waveform modeling,was born on 23 January 1938 and died on 13 August 2020.Don obtained his Ph.D.in 1967 at the University of California San Diego,USA.In 1970,after a two-year appointment as a research associate at MIT and one year on the faculty at Princeton University,Don moved to the Seismological Laboratory at Caltech where he was to spend the rest of his career.