This book captures the range of views and evidence on class size across the world; seeks to clarify these deeply held views and move toward a clearer view of what we know and do not know about class size effects; and identify future steps in terms of policy and research. Of all the issues in education, debate about the effects of class sizes in schools is probably the most long standing and contentious. The time is exactly right for a text which captures a range of international research and perspectives, and allows a forum for alternative points of view, while at the same time providing an integrated editorial commentary on the key issues. Copyright © 2016 P. Blatchford, K. W. Chan, M. Galton, K. C. Lai, and J. C. Lee.