Published in 1986, this book addresses the controversial classroom dilemma of ability segregation versus integration. It presents an extensive review of the current literature and formulates a conceptual framework for analysing the social processes that affect classroom composition and their effects on academic achievement. Applying an innovative framework to two empirical studies of Israeli high schools, the authors highlight the profound implications for classroom organisation, and include an explanation of teachers’ attitudes to pedagogical issues and social influences. Sociologists, teachers and educational psychologists will find this a stimulating but practical study of ability grouping and streaming in schools.