Breastfeeding is the best way to feed an infant with short- and long-term health benefits of breastfeeding for both mothers and their infants. This chapter introduces current recommendations for breastfeeding and the evidence that supports these recommendations. The chapter describes the physiology of lactation and the unique nutrition and immunoprotective properties of breast milk. It also considers breastfeeding from the mother’s perspective, identifies nutrient requirements for lactation, and discusses the impact of maternal diet on breast milk composition. This chapter describes some of the common problems experienced by lactating women and presents strategies for supporting and encouraging women to breastfeed.