The development of immunization has been one of the most striking features in the control of infectious disease in the twentieth century. This book takes into account the need for a simple, concise account of immunization procedures not only in the UK and USA but also in other countries, and to this end a special chapter on immunization in developing countries has been included. Following two introductory chapters, there are nine chapters on various diseases and the vaccines that have been developed to combat them. In each of these chapters, a short discussion of the epidemiology of the disease and the history of immunization against it is followed by a description of the vaccine, its efficacy, contraindications to its use and future developments. These are followed by four general chapters on vaccines for travel, vaccines for selective use, passive immunization and immunization in tropical environments and the book concludes with a chapter on the smallpox vaccination and one on new vaccines. The demand for this book follows the popularity of a series of articles on immunization which appeared in Update. These have been expanded and largely rewritten. I have drawn on many expert sources and have made an effort to provide a balanced and non-controversial opinion with a discussion of alternative procedures where indicated.