The Ultraviolet Imager on the Viking Spacecraft provides global images of aurora in both night and day hemispheres at rates of up to three per minute. First results summarized in this and a set of eight companion papers reveal new aspects of the patterns and dynamics of the aurora, including eastward as well as westward expanding substorm intensifications, but very little evidence of bulk westward motion of auroral surges; rapid poleward and equatorward expansions during some substorms, resulting in the formation of an intense eye-shaped bulge containing diffuse aurora and north-south aligned arc segments; substorm-like intensifications at the point where transpolar arcs join the nightside oval; rapid small scale auroral brightenings, or ''hotspots'' over a wide range of local times; and very rapid changes in auroral forms in the noon sector. ¿American Geophysical Union 1987