Human respiratory syncytial virus (RSV) is a significant human pathogen in infants, young children, older adults, and the immunocompromised. Over the last decade, many important mechanisms contributing to RSV infection, replication, and disease pathogenesis have been revealed, and a body of information has accumulated regarding how RSV proteins modulate molecular signaling and immune responses to infection. In this chapter, we briefly introduce RSV replication and pathogenesis and summarize the state of the RSV vaccine and antiviral compounds in the clinical stages of development. This chapter frames the features of this book and the molecular methods used for understanding RSV interaction with the host.