Protein plays a vital role in growth and development and is able to 'program' healthy growth by influencing gene methylation for positive long-term health outcomes. The understanding of these mechanisms is critical to support and improve the health of future generations in both the short and long term.The first part of this book reviews the role of hydrolyzed proteins in infant feeding and the evidence-based benefits of their use in non-breastfed infants at risk of allergy and in infants with functional gastrointestinal disorders. The second part focuses on human milk and its potential alternatives in the feeding of healthy term infants. The final section is dedicated to preterm infants, their nutrition needs, and physiological capacities to ingest adequate amounts of protein for appropriate growth and development. Presenting the latest scientific findings on protein in early nutrition, this publication provides essential reading for pediatricians and researchers alike.