It is a pleasure to write the foreword to Nutrition and Table 1 Nutritional Status and Outcome of Infection Immunology: Principles and Practice. In fact, this book comes at a timely moment, when the impact of nutrition and Definite adverse outcome immunology is being widely felt because of the AIDS epi­ Measles, diarrhea, tuberculosis demic. This is particularly of note in Africa, where large Probable adverse outcome HIV, malaria, pneumonia sums of money are being spent on nutritional intervention Little or no effect programs in the hopes of improving immune responsive­ Poliomyelitis, tetanus, viral encephalitis ness. We should not forget, however, early advances in our Note: HIV= human immunodeficiency virus understanding of protein energy malnutrition (PEM). PEM can be used as a model to understand the nutritional basis of immunity, as well as the immunological influences on nutri­ tional status. Despite advances in agricultural production, tance. However, both in vitro studies and tests in laboratory PEM continues to affect hundreds of millions of the world's animals may have little resemblance to what is experienced population. The functional impact of undernutrition varies in humans under field conditions. from mild morbidity to life—threatening infection.