Student interaction patterns in eight elementary school classrooms were examined to investigate (1) the relationship between interaction patterns and sociometric indicators of friends, (2) the process by which children become stratified, and (3) the structure of peer relationships in classrooms. Chapter 1, the introduction, briefly discusses the central concerns of the study. Chapter 2 presents a model of the stratification process and discusses a variety of factors which must be taken into account for understanding this process. Chapter 3 describes the methods employed in the study and contains descriptions of the children and the classrooms studied. Chapters 4 through 7 present the results of the study. Chapter 4 concerns the relationship between sociometric choices and actual interaction patterns; chapter 5 looks at the structure of peer groups; chapter 6 examines the relationship of reading groups to interaction patterns; and chapter 7 examines the cross-sex interaction patterns. Each of these four chapters starts wih a review of the relevant literature. Variations among the classrooms along certain relevant dimensions are then described. These variations are related to critical factors which lead to the variation and explain the particular pattern found in each classroom. The final chapter, chapter 8, presents a summation of the findings, an elaboration of the model proposed in chapter 2, implications for classroom practice, and suggestions for further research. (Author/RH)