Recently many physicists have become intrigued with trying either to explain or to duplicate the Schwarz–Hora effect, in which an electron wave is apparently modulated by a light wave. In an invited paper at the March APS meeting Helmut Schwarz (Rensselaer Polytechnic Institute, Hartford Graduate Center) discussed his most recent observations of the effect, first reported by himself and Heinrich Hora (Max Planck Institute, Garching, Germany) in June 1968 (Bull. Amer. Phys. Soc.13, 897, 1968 andAppl. Phys. Lett.15, 349, 1969).