The primary function of the mammary gland is to provide nutrition for the young in the form of milk protein and fat. However, there are other benefits that are provided by lactation, such as the provision of immune factors that are secreted into the milk, which provide protection from infection. In this book, the authors discuss the natural processes, physiological response and role in maternity of lactation. Topics include gene expression in the mammary gland; human milk oligosaccharides and their health effects; the role of micro-RNAs in the lactation process; hormonal control of lactation, the role of breastfeeding in lactation; and Wnt signalling and ultrasound in lactation.