It is my pleasure to write the foreword to "Nutrition and Immunology: Principles and Practice." This book comes at an opportune time, as the impacts of nutrition and negative outcomes in immunology are profoundly felt due to the AIDS epidemic and diseases such as measles, diarrhea, and tuberculosis. This is particularly notable in Africa, where significant sums of money are spent on nutritional intervention programs in the hope of improving immune response capabilities. However, we should not forget the early progress in our understanding of protein-energy malnutrition (PEM). PEM can be used as a model to understand the nutritional foundations of immunity as well as the immunological influences on nutrition.