Since the discovery of animal rotaviruses (RVs) in the 1960s (1,2), and of human rotaviruses (HRVs) 25 yr ago (3,4), much has been learned about virus structure, classification, evolution, replication, pathogenesis, and specific immune responses, and their correlation with protection and epidemiology. As pathogens that infect the gastrointestinal tract, these viruses continue to serve as useful models to understand mucosal virus-cell interactions. Recently, a RV vaccine to prevent disease in children has been licensed in the United States (US); this vaccine is expected to be applied worldwide. The chapters of this book have reviewed some of the research on RVs, with an emphasis on molecular methodological approaches. This summary chapter draws attention to some topics on which ongoing research is likely to produce significant results in the years to come, but also on which more research is needed.