Adolescent studies in the last half-century centred largely on atypical behaviour. Many aspects of normal adjustment not yet fully explored. Athropological studies reveal short, smooth adolescent period in primitive societies. Adolescence as a period of adult-role acquisition. The relation between length of the adolescent period and cultural complexity. Commencement of period determined by signs of physical development. Adolescence not terminated by physical event, but rather by readiness to accept expected adult role, varying with the culture. Expected role defined by elders, with possibility of conflict in adolescent adjustment. Conflict emphasized between conservatism of adults and readiness of youth to accept new ideas. Importance of Sub-cultural influences in relation to adolescent adjustment. Effect of age, sex, family, occupation, habitation, religion and class in delimiting the participation of youth in society. Need to consider fully the interaction of role-determinants. Difficulty presented by adolescent study: instability of adolescent period - reluctance of parents to submit youth to inquiry - problems arising from distribution of sample - age, schooling, habitation. Special consideration of these difficulties in Queensland. Formulation of problems and hypotheses. Social maturity. Value-systems. Sex education. Age of pubescence. Opinion on social issues. Cognitive capacity.