The authors have indicated they have no financial relationships relevant to this article to disclose.T HIS SUPPLEMENTAL ISSUE of Pediatrics presents the first set of results from the Infant Feeding Practices Study II (IFPS II), which were chosen to cover a wide range of the topics included in the study. The IFPS II was conducted collaboratively by the Food and Drug Administration and the Centers for Disease Control and Prevention (CDC) and was co-funded by other agencies in the Department of Health and Human Services, as indicated in "Acknowledgments."The design of the IFPS II was similar to that of the original study (the IFPS I), which was conducted in 1992-1993. In the current longitudinal survey, a large cohort of 4900 women was enrolled prenatally, and Ͼ2000 were followed through the first year of their infant's life. The mothers were mailed 1 prenatal and 10 postnatal questionnaires at approximate monthly intervals; in addition, prenatal and postnatal subsamples were administered a dietary intake questionnaire. The questionnaires were modeled on the IFPS I, but the IFPS II included several new topics such as postpartum depression, consumption of herbal and alternative medicines, breast-pump use, and infant sleeping arrangements. The details of the study methods and a list of publications from the IFPS I are presented in an article by Fein et al 1 in this supplement.Why an IFPS II? In the decade since the IFPS I, significant changes have occurred in the products, policies, information, and education related to infant feeding choices. Breast pumps have become more effective and more affordable; new ingredients have been added to infant formula; and changes in state and federal laws have reduced some barriers to breastfeeding. Policies and recommendations about infant feeding (duration and exclusivity) have changed. In 2004 -2006, the Department of Health and Human Services conducted a national breastfeeding-promotion campaign, the impact of which had to be evaluated. Thus, the IFPS II was conducted to better understand current infant feeding practices approximately 1 decade after the IFPS I.The 13 articles in this supplement provide results on several feeding issues: breastfeeding patterns, intensity, and duration; reasons for stopping breastfeeding; and transitional and complementary feeding, including provision of iron-rich foods and supplements to breastfed infants. They examine the association between mothers' behaviors with respect to their infants' feeding and mothers' interface with certain types of organizations that may support or limit their choices, including the maternity care practices of the place at which they delivered and the breastfeedingrelated options associated with their place of employment. The articles also describe and analyze patterns of breast milk expression; infant formula handling practices; infant sleeping arrangements; and food-related health problems including food allergy. Another article analyzes the effects of breastfeeding intensity, infant-initiated bottle emptying, and ...