The nature of the relationships between school resources and the cognitive achievement of children are investigated here. The study provides new information concerning the impact that school resources, especially teachers, have on their learning. The research design employed focuses on 875 individual inner city black children in their individual classrooms. The first question that is investigated is whether there are important quality differences in the learning environments provided by different classrooms. After answering this affirmatively, the reasons for the quality differences are explored in terms of teachers, peer groups, class sizes, and the number of transient students. Chapter 2 discusses the recent history of this type of research and provides a perspective which is important for understanding the ways in which this particular study differs from previous research. Chapters 3 and 4 contain the empirical analysis of the relationships between school resources and the cognitive achievement of children. Summaries of research conclusions and discussions are in Chapter 5. It is concluded that teachers have a critical impact on student achievement. (Author/AM)