This paper and the following one both demonstrate an adverse impact of mothers' work outside the home on the health and development of their infants and preschool children and explore the reasons for it. Although both are local studies, they have been accepted for publication because of their wider implications. The first paper, based on work in rural Iran, concludes that the mechanisms for this effect are not primarily financial. Because it would be very difficult to change the pattern of women's economic activities in such a society, it is suggested that seasonal day-care centres are the most feasible means of alleviating the problem. The lack of funds for foods with an adequate density of protein and calories, plus the tendency to offer such foods only in over-diluted form, is widespread. The following paper, by Wandel and Holmboe Ottesen, based on work in rural Tanzania, comes to quite different conclusions. The authors find that "the amount of mothers' field work did not seem to have any profound or conclusive relationship to children's nutrition stands" because of buffering or compensating circumstances. In this society, unlike many others, women's time constraints do not appear to be important in explaining the variation in children's nutrition status. However, because three meals per day was seen as an absolute maximum that could be provided to young children, advice about more frequent feeding or more time-consuming food preparation is not likely to be accepted. The Bulletin always tries to judge the usefulness of a local study in a country to policy makers, programme planners, and researchers in other countries. It usually rejects descriptive studies that do not either have applicability to some other situations or introduce new methodological considerations. The publication of these two contrasting works concurrently is warning once again that the conclusions from studies in one population may or may not be applicable to other populations. This can be determined only by investigation of their local appropriateness.