Presenting an empirical study of student mathematics learning in sixth grade classrooms, this unique reference examines two school systems shaped by different political histories on either side of the Botswana-South Africa border. The analysis underscores the capacity of teachers--how they teach, how much they teach, and what they teach. This wealth of detail offers much greater insight than previous research into why students seem to be making larger gains in the classrooms of southeastern Botswana than in those of the northwest province of South Africa. Rather than identifying a single major factor to explain this difference, this volume reveals a composite of interrelated variables revolving around teachers' mathematics knowledge as well as their capacity to teach the subject, contending that they're crucial to improving education in both regions. Extensively researched, this survey delivers a much-needed and hopeful message: good teachers can make a difference in student learning.