On the Cover: The Sun has set on Mars, but twilight lingers, casting a reddish glow on the Martian surface (left) and the top of <i>Viking Lander 1</i> (right). Red dust in the atmosphere scatters the sunlight, producing the color of the sunset. The coloured rings in the sky are not real; they are artifacts of severe contrast enhancement produced by computer processing of the camera's transmitted image.
3 The Last Viking: Long-time science journalist Jonathan Eberhart gives a poetic summary of the Viking mission to Mars.
10 Venus Revealed: Brown University planetary geophysics graduate students James B. Garvin, Maria T. Zuber, and Paul Helfenstein take us on a photographic tour of the Venusian surface with Venera images.
13 Society Notes The Hungarian connection.
14 News & Reviews "The Great Extinction" and other mysteries.
15 World Watch Venus Radar Mapper, Galileo, Cassini, and future Soviet mission plans.