Basic Physiology of the Growth Hormone/Insulin-Like Growth Factor Axis -- Experimental Models for Understanding the Role of Insulin-like Growth Factor-I and Its Receptor During Development -- Insulin-like Growth Factor Binding Proteins in Development -- Growth Hormone, Insulin-like Growth Factors and the Female Reproductive System -- Skeletal Muscle -- Cardiovascular and Respiratory Systems -- Hematopoiesis -- Brain Development -- Regulation of Vertebrate Sensory Organ Development: A Scenario for Growth Hormone and Insulin-Like Growth Factors Action -- Role of Insulin-Like Growth Factors in Neuronal Plasticity and Neuroprotection -- Aging and Life Span -- Interactions of Insulin-Like Growth Factor-I and Estrogen in the Brain -- Cancer -- Genetic Basis of Proportional Short Stature -- Future Perspectives.Insulin-like growth factor (IGF)-I is a widely expressed growth factor with diverse effects on many tissues throughout development and in adult life. The purpose of this work is to provide detailed and updated information on the role of the growth hormone (GH)-IGF axis in fetal and postnatal development, as well as its physiological functions and implications in pathology.