In the 1920's, the Scottish physicist C.T.R. Wilson predicted the existence of brief flashes of light above large thunderstorms. Almost 70 years later, Bernard Vonnegut of SUNY Albany realized that evidence for Wilson's then-unconfirmed predictions might appear in video imagery of Earth's upper atmosphere recorded by space-shuttle astronauts. He encouraged NASA's William Boeck and Otha Vaughan to look for evidence. Their search was successful. At the 1990 fall meeting of the American Geophysical Union, Boeck and Vaughan presented evidence for upper-atmosphere flashes. Evidence of a different nature came from the University of Minnesota's John Winckler and his colleagues, who had serendipitously observed a flash in moonless night-time skies over Minnesota in 1989. These early findings inspired two independent field programs to target the new phenomenon. In the summer of 1993, Walter Lyons of FMA Research set up detectors on Yucca Ridge in the foothills of the Rocky Mountains. That same summer, Davis Sentman of the University of Alaska Fairbanks (UAF) sought to record the flashes from an aircraft flying over the Great Plains. Within a day of each other, the two research teams had documented what turned out to be a common phenomenon in the mesosphere. In doing so, they initiated not only a new kind of continental-scale field experiment but also—and more important—a new interdisciplinary area of research.