Highly energetic radiation has been observed in conjunction with thunderstorm electrical activity in recent years, at timescales from microseconds and milliseconds (usually coincident with lightning) to minutes, and from the vantage points of satellites, aircraft, balloon-borne instruments, and instruments on the ground. High-energy electrons, positrons, gamma-rays, and neutrons have been observed, but the physical processes and enabling meteorological contexts involved remain mysteries. We invite experimental, theoretical, and observational contributions investigating all aspects of energetic radiation produced in connection with atmospheric electricity, including terrestrial gamma-ray flashes (TGFs), terrestrial electron beams (TEBs), positron and neutron production, high-energy radiation from stepped leaders, runaway relativistic electron avalanche, observations of lightning and thunderstorms associated with energetic radiation, effects of thunderstorm electric fields on cosmic-ray showers, and physical models of radiation production.