The practice of neonatology requires a careful balance between modern technology and the prevention of unintended damage to a newborn. Early therapeutics were based on adult medicine, with often catastrophic results to the baby. As research and understanding of physiology and therapeutics have expanded, care of the preterm and sick infant has improved drastically. Avery’s Neonatology is a practical guide to understanding the pathophysiology of the newborn so that appropriate treatment decisions can be made.