This document, a result of the October 1979 joint meeting of the World Health Organization and the United Nations Children's Emergency Fund (WHO/UNICEF) on Infant and Young Child Feeding, provides both a report of the themes discussed by the participating working groups, and a compendium of background information relevant to these themes. The five themes discussed by the working groups (presented in the first section of the document) deal with a variety of subjects considered basic to infant and young child feeding. These subjects include such issues as the encouragement and support of breastfeeding; the promotion and support of appropriate weaning practices and the related need for information, education, communication, and training; the health and social status of women in relation to infant feeding; and the appropriate marketing and distribution of breast-milk substitutes. The second section of the document (containing the compendium of background information) covers such material as the nutritional needs of infants; composition of human milk; factors influencing the volume of human milk; breastfeeding and child spacing; and lactation and contraception. This section also addresses two fundamental questions: to what extent and how long can breastfeeding meet the nutritional needs of the infant under different circumstances? (Author/MP)