The project is composed of the following studies: (1) A constructively critical, hypothesis-oriented analysis of the worthwhile literature on heredity and environment in schizophrenia. (2) An intensive multidisciplinary study of a family with MZ quadruplets (daughters) concordant as to schizophrenia but discordant as to severity and outcome. This study was published in book form. We are continuing our contracts with this family to see what happens in the clinical course of these girls and how the course is related to earlier and current life experiences. (3) Studies of adoptees and their biological and adoptive families. (4) A study of children (of schizophrenic and control parents) reared in town or kibbutz in Israel.