Why another book about vaccines? There are already a few extremely well-written medical textbooks that provide comprehensive, state-of-the-art technical reviews regarding vaccine science. Additionally, in the past decade alone, a number of engrossing, provocative books have been published on various related issues ra- ing from vaccines against specific diseases to vaccine safety and policy. Yet there remains a significant gap in the literature - the history of vaccines. Vaccines: A Biography seeks to fill a void in the extant literature by focusing on the history of vaccines and in so doing, recounts the social, cultural, and scientific history of vaccines; it places them within their natural, historical context. The book traces the lineage - the "biography" - of individual vaccines, originating with deeply rooted medical problems and evolving to an eventual conclusion. Nonetheless, these are not "biographies" in the traditional sense; they do not trace an individual's growth and development. Instead, they follow an idea as it is conceived and dev- oped, through the contributions of many. These are epic stories of discovery, of risk-takers, of individuals advancing medical science, in the words of the famous physical scientist Isaac Newton, "by standing on the shoulders of giants. " One grant reviewer described the book's concept as "triumphalist"; although meant as an indictment, this is only partially inaccurate.