Abstract: This monograph is a compilation of chapters written by various scholars in pediatrics, immunology, nutrition, and infectious diseases. It is intended to provide an update on recent developments in several selected areas of pediatric infections. It contains a comprehensive overview of the development and function of the major components of neonatal defense. Several chapters examine the characteristics and functional role of immune response induced in the neonate after naturally acquired bacterial and viral infections and after immunization with microbial vaccines. Also discussed are the nutritional-immunologic interactions and the outcome of neontal infection. This section includes a review of nutritional requirements of a fetus and neonate, the impact of nutrition on perinatal infections, the role of breastfeeding in infant nutrition, neonatal immunologic development, and the impact of malnutrition on mucosal infections. Finally, the effects of specific nutritional deficiencies on the neonatal immune system and the implications for the pathogenesis of neonatal infections are reviewed. (as).