Because cow’s milk* most often serves as the major source of ingredients in infant formula, and because the scientific literature is far more extensive on this than on any other mammalian species, a work of this nature perhaps best begins with a comparison of human milk and cow’s milk; this approach is taken with an eye to the need to improve the nutrient composition of infant formula. At the same time, both human milk and infant formula are best considered in light of the latest scientific recommendations for infant nutrition. Thus, the first part of this book is devoted to these considerations. The second section deals with the immune factors of mother’s milk, that is, the disease-fighting potential of this food. Here certain advantages of human milk will become clear. Formula, too, can be processed with a certain level of built-in immune potency. The research proving the efficacy of such formulations is considered in this section, along with a discussion of breast infections, allergic responses, contaminants of breast milk, and issues of drug use. In the third section I focus on the formulation and processing of infant formula. Both nutrient and immune factors are discussed. Advent of human milk banks makes appropriate further consideration of precautions in obtaining, storing, and pasteurizing human milk. Finally, because the feeding of breast-fed infants must be supplemented at some point in time, and often with lactose-containing food(s), a chapter of this book is devoted to lactose “intolerance” at weaning and beyond.