This chapter examines brain assessment techniques that have been used with individuals who are at risk for alcoholism. It also examines the influence of developmental processes on this assessment. Neuropsychological assessment typically identifies brain damage in individuals and assesses the extent and nature of brain dysfunction. In vivo techniques have been used primarily in adult alcoholics. Offspring of alcoholics can be considered at biosocial risk because both biological and social factors place them at risk for alcoholism and other problems. Several In vivo assessment techniques are available for the purposes of diagnosis and research that offer challenging, exciting, and dynamic opportunities to study the brain. Assessing the concurrence of brain and behavioral maturation in individuals at biosocial risk adds considerable complexity to the problem of understanding the brain-behavior relationship. Assessing brain-behavior relationships over the course of development in atrisk populations impels people to address the role of developmental change in the expression of the risk itself.