Although immunization currently prevents three million child deaths annually, more widespread use of existing vaccines could prevent an additional two million child deaths each year. Public health personnel are working hard to achieve and sustain the tremendous promise of immunization and to cope with significant changes in programming, including new objectives, new vaccines, new procedures, new technologies for vaccine delivery and the cold chain, and health sector reforms. Immunization Essentials: A Practical Field Guide, a revision of the Agency's EPI Essentials published in 1988, provides technically and operationally sound information for immunization program managers at national and sub-national levels in developing countries and field staff of donor agencies. Major topics covered include: (1) immunization program management; (2) delivery of immunization services; (3) monitoring, evaluation, and information management; (4) vaccine supply and quality; (5) the cold chain and logistics; (6) injection safety; (7) disease surveillance; (8) the role of behavior change; (9) costs and financing; (10) new vaccines and technologies; and (11) vaccines and vaccine-preventable diseases. Production of the book was coordinated by the Monitoring, Evaluation and Design Support (MEDS) and Population, Health and Nutrition Information (PHNI) Projects. The BASICS II and CHANGE Projects served on the technical writing group.