Presents the results of the application of the analysis of the social assimilation of immigrants to the processes whereby beginning teachers transfer their membership from the university student subculture to the professional secondary teacher subculture. Extends the social assimilation framework from the study of immigrants to the general field of professional socialization -- a move from membership in one social structure to another with a consequent need to cope with and adapt to a new social environment resulting in skill, attitude, and behavior changes; and a new concept of self. (Author/EA)