General concepts of 'institutionalization' and 'marginalization' do have a role to play in the study of the history of education. Their chief value, however, is a heuristic one: they put us in touch with unsuspected links and patterns in concrete historical phenomena. Thus, institutions like madhouses and asylums for the insane, reformatory schools, prisons, but also new mental structures as punishments, cures and the re-education of deviants, can be regarded as places where patterns of norms and values can be examined at close range, especially concerning those on the edges of society, the marginals.Questions such as 'who are the marginals' and 'what is marginalization', however, remain elusive. Marginaiity is a fluctuating frontier and a fluctuating concept. For this reason, it is useful to introduce an intermediary zone between marginaiity and normal life, namely an area of fragile existence. Sometimes marginalization was applied with the aim of ultimately reintegrating people into society, especially in the nineteenth century in the upbringing of neglected and difficult children, as well as in psychiatry and in the penal system.History of marginaiity is more than the history of deviant behaviour. Research in the history of marginaiity can set us, by implication, on the trail of the history of normal behaviour, of everyday upbringing and the norms governing these activities: and of the fragile relationship between normality and marginaiity.