Wilson, by making and analyzing remote measurements of thunderstorm electric fields, was the first to infer the charge structure of the thundercloud and the amount of charge involved in lightning. In the 1930’s, lightning research was motivated primarily by the need to reduce the effects of lightning on electric power systems and by the desire to understand an important meteorological process. The pace of that research was fairly steady until the 1960s when there was renewed interest because of the generally unexpected vulnerability of solid state electronics to damage from lightning-induced voltages and currents with the resultant hazard to both modem ground-based and airborne systems.