Swine influenza is a continual problem for the Swine industry and can pose a public health threat as evidenced by the 2009 H1N1 influenza virus pandemic. Given its importance, it is not surprising to find papers describing the disease from the early 20th century. In this chapter, we discuss the history of Swine influenza, the important role swine influenza virus has played in our understanding of influenza virus pathogenesis and virology, and its impact on public health worldwide.