The South Pole-Aitken Basin is a prominent lunar anomaly in many respects. In addition to being the principal shaper of topography (top right) of the farside of the Moon (see caption, slide #25), the basin floor is the primary compositional anomaly of the farside and the highlands of the Moon. The albedo map (top left) shows that the floor of the basin is markedly darker than the highlands surrounding it. Both iron (bottom left) and titanium (bottom right) concentration maps show enhanced values associated with the basin floor materials. These results suggest that the floor of the South Pole-Aitkin Basin is made up of relatively mafic rocks. Whether this is a consequence of volcanic resurfacing or of the basin stripping off the feldspathic upper crust, exposing a more mafic substrate (possibly even exposing the upper mantle of the Moon), is being investigated.