Arthur J Reynolds & Herbert J Walberg 
Can Unlike Students Learn Together? 

For the first time, this book brings together three controversial topics: homogeneous grouping of students within classrooms by ability or achievement criteria, tracking of students into courses of study by the same criteria, and retention of students in their present grade so that they repeat a year’s work instead of being promoted. The editors solicited syntheses of research on these topics from outstanding scholars with a variety of views.