Throughout history, theories of the first type have found the causes of criminal behavior in inborn evil and primitivism, biological inferiority, and mental deficiency. Environmental theories have tended to be either sociological or psychological. The sociological theories explain deviance in terms of frustration and anomie (strain theory), conformity to subcultural values (cultural deviance theory), inability to accept community norms and controls as the result of social and psychological factors (control theory), and society's failed attempts to deal with nonstandard behavior (labeling theory). Most psychological theories emphasize the psychodynamics of the individual, seeking to abstract from case studies patterns of internal organization which explain human nature and response to conflict. The most important theories in this group focus on identity problems during adolescents' growth to maturity (identity crisis theory), development of the human personality and defense mechanisms in contact with meaningful others (psychoanalytic theory), and human behaviors as learned habits related to genetic characteristics of personality (psycho-biological theory). Since delinquency has been recognized as a very broad term, efforts have been made to define different types of offenders. Typologies may be psychiatric, behavioral, psychological, or factor-analytic. Unfortunately, not many people fit into one category or another, and the typologies tend to oversimplify the situation. Delinquency must be viewed as a multifactorial phenomenon rendered complex by the interaction of biological, social, and interpersonal forces. Attempts to explore the phenomenon from this perspective should be encouraged despite cries of 'unscientific' from some quarters. For such approaches it is necessary to demonstrate a frame of reference or a view of the way human beings grow up and a value system against which observations can be checked. A useful frame of reference as such is contained in the proposal of a set of basic human needs as they develop from primary dependency relationships. Forty-six references are supplied.