The article by Toga, Thompson, and Sowell reviews recent progress in imaging studies of brain development, focusing on cortical and subcortical changes in healthy children and comparing them with abnormal developmental changes in early-onset schizophrenia, fetal alcohol syndrome, attention-deficit hyperactivity disorder (ADHD), and Williams syndrome. The authors discuss the cellular processes underlying these structural changes and their relationship to cognitive and behavioral changes throughout childhood and adolescence. They highlight the dynamic nature of brain maturation, emphasizing the importance of the first two decades of life in shaping brain potential and vulnerability. The review covers topics such as synaptic changes, myelination, and the use of MRI techniques to study brain development. It also discusses the application of statistical maps to assess group effects in brain structure differences between healthy children and those with neuropsychiatric disorders. The article concludes by exploring the genetic influences on brain development and the limitations of brain-imaging studies.The article by Toga, Thompson, and Sowell reviews recent progress in imaging studies of brain development, focusing on cortical and subcortical changes in healthy children and comparing them with abnormal developmental changes in early-onset schizophrenia, fetal alcohol syndrome, attention-deficit hyperactivity disorder (ADHD), and Williams syndrome. The authors discuss the cellular processes underlying these structural changes and their relationship to cognitive and behavioral changes throughout childhood and adolescence. They highlight the dynamic nature of brain maturation, emphasizing the importance of the first two decades of life in shaping brain potential and vulnerability. The review covers topics such as synaptic changes, myelination, and the use of MRI techniques to study brain development. It also discusses the application of statistical maps to assess group effects in brain structure differences between healthy children and those with neuropsychiatric disorders. The article concludes by exploring the genetic influences on brain development and the limitations of brain-imaging studies.