The half-century following the Civil War witnessed an epochal transformation in American telecommunications. In the 1870s, the telegraph network became a spawning ground for a remarkable spate of inventions that included the phonograph and the telephone, and around 1900 the telephone network became the first electrical communications medium that network providers intended to be accessible to the entire population. This transformation was a centerpiece of the still unprecedented burst of inventive activity that economic historians call the Second Industrial Revolution.