Aaron Pallas is Professor of Sociology and Education at Teachers College, Columbia University. He has also taught at Johns Hopkins University, Michigan State University, and Northwestern University, and served as a statistician at the National Center for Education Statistics in the U.S. Department of Education. Professor Pallas has devoted the bulk of his career to the study of how schools sort students, especially the relationship between school organization and sorting processes and the linkages among schooling, learning and the human life course. He is a Fellow of the American Educational Research Association and an elected member of the Sociological Research Association. His most recent projects are explicitly designed to inform policymakers and other stakeholders about conditions in New York City public schools (http://www.tc.columbia.edu/faculty/?facid=amp155).