The onset of cold weather brings out the boots, coats, gloves--and the stoplight-red "Flu Shots Available Here" signs in drugstore windows. For many scientists and public health specialists alike, flu season has become a little like Russian roulette. The likelihood of a deadly pandemic outbreak of influenza is not far from reality considering the nature of some of the different viral strains. In this book, we delve into the science of the flu, starting with past pandemics and what we can learn from them.