A practical guide, now in its third edition, to the detection, treatment, and prevention of vitamin A deficiency and its consequences, including associated mortality, infectious morbidity, and xerophthalmia. Addressed to clinicians, nurses, and public health officials, the text has been thoroughly revised to reflect recent advances in knowledge. These include growing recognition of the importance of adequate vitamin A intake for normal child health and survival, and evidence that milder degrees of deficiency may have severe consequences, including increased mortality, before xerophthalmia becomes apparent in a population. In line with these advances, the guide offers advice on the detection and treatment of sub-clinical or marginal degrees of deficiency as well as on the emergency management of xerophthalmia and measles. The guide has six chapters. Background information is provided in the first two, which describe the biochemistry of vitamin A metabolism and explain the complex relationship between specific serum levels and the physiological consequences of deficiency. The third chapter provides a detailed guide to the clinical classification and diagnosis of xerophthalmia. Recognition of the characteristic signs and symptoms of increasingly severe disease is facilitated through the inclusion of 32 color plates. A chapter on epidemiology concentrates on the many factors that place children, particularly those from depressed rural communities and urban slums, at risk of vitamin A deficiency. Of particular practical value is a chapter on assessment, which explains how well conceived surveys, appropriate to local conditions, can guide the design of efficient and cost-effective interventions. A chapter on treatment provides schedules for vitamin A dosing in the emergency management of xerophthalmia, severe infectious episodes, and severe protein-energy malnutrition, and offers advice on dietary improvement, essential eye care, and the prevention of recurrence. The final chapter, on prevention, describes the wide range of options that can be followed to meet both short-term and long-term program goals.A. Sommer is the author of 'Vitamin A Deficiency and Its Consequences: A Field Guide to Detection and Control' with ISBN 9789241544788 and ISBN 9241544783.