For parents, few infections scored higher than poliomyelitis on the 'dread' factor from the early years of the twentieth century as each successive wave of the disease outdid its predecessor in the number of children it crippled and killed. But, from the 1950s, this picture abruptly changed when preventive vaccines were developed which have brought the disease to the edge of global eradication. Part I, Epidemic Emergence, 1881-1920, looks at the transition from endemic to epidemic poliomyelitis in Europe and the United States. Part II, Global Expansion, 1921-55, covers the pre-vaccination period of epidemic poliomyelitis at world, continental and island scales. Part III, Global Retreat, 1955-88, focuses upon the control of poliomyelitis by mass vaccination campaigns. Part IV, Global Eradication, concludes the book by focusing upon the road to eradication, to which the Forty-first World Health Assembly committed in 1988. And so, at the beginning of a new millennium, poliomyelitis looks set to be the first disease since smallpox in 1979 to be eradicated by direct human intervention, with the interruption of wild poliovirus transmission expected in 2005. The evolution of poliomyelitis to global epidemiological significance from the 1920s marks it out as one of the world's major emergent infections of the twentieth century. What causes diseases to wax and wane in time and space is a theme of contemporary scientific interest as we seek to understand the appearance of new conditions such as Ebola fever, Legionnaires' disease, and HIV, and this book contributes to our comprehension of likely causes.