Three and a half million children die each year from diphtheria, whooping cough, tetanus, poliomyelitis, measles, and tuberculosis. There is no need for this to continue; the vaccines and the means to give them are available in every country. This practical training manual, prepared by the staff of the World Health Organization's Expanded Programme on Immunization, explains what vaccinators need to know about the immunization process. It is illustrated with clear diagrams throughout and includes practical exercises based on case studies and a teacher's guide.