What questions have yet to be answered about the Moon? Bradley Jolliff, professor of earth and planetary sciences at Washington University in St. Louis, describes how lunar samples and orbiters continue to provide fascinating insights into the geologic history of Earth's closest neighbor. Jolliff, who works with the Mars rover Opportunity, also shares his dreams of a future lunar rover that would visit sites that continue to puzzle scientists, including the immense South Pole-Aitken Basin and the icy, permanently shadowed lands near the Moon's poles.