Alcoholism etiology is discussed from a developmental behavior genetic perspective. At the outset point, temperament characteristics, by means of ongoing and reciprocal interaction with the social environment, shape the course of behavioral development. The behavioral characteristics successively acquired during development are vectors that determine the ontogenetic trajectory that culminates ultimately in the clinical disorder of alcoholism. The temperament features that appear to be associated with a heightened risk for alcoholism are examined. Their interactions with the environment during the course of development are considered within an epigenetic framework and, as discussed, have important ramification for improving the prevention and treatment of alcoholism.