The thesis is an analysis of the changing social definition of youth and the pattern of transition from youth to adulthood in the context of the schooling systems and educational policies of England and Wales, and the USA since the Second World War. The period under study, 1945-1992 can be divided into two parts. The first is the period of the dominance of the welfare state. The second is the period typified by an attempt by the state to withdraw as a major provider of welfare. In Part One of the thesis a general analysis is undertaken of the position of youth under welfare capitalism within liberal democracy. The study focuses particularly on the educational provision for the fourteen to nineteen year group. A comparison is made between the welfare capitalist model of youth and that of two totalitarian states in which comprehensive national youth policies were developed. In Part Two, a study of the educational provision for youth in the USA, England and Wales during the period 1945 to 1972 is undertaken. It focuses upon the successes and failures of the policies of each state. In particular the tension between educational and state ideologies in the construction of youth is explored. In Part Three there is a study of youth in the period from 1972-1992. For both countries this is a time of concern with economic decline. In the USA and England and Wales governments attempted to withdraw from the extensive provision of education and welfare. The study analyses the effect of the new policies on the definition of youth.