Mariana Levin Editor

Andrea A. diSessa is Corey Professor of Education Emeritus and Professor of the Graduate School at the University of California, Berkeley, USA. He is a member of the National Academy of Education and a Fellow of the American Educational Research Association.

Mariana Levin is Assistant Professor of Mathematics Education in the Department of Mathematics at Western Michigan University.

Nathaniel J. S. Brown is Associate Research Professor of Educational Research, Measurement, and Evaluation at the Lynch School of Education, Boston College, USA.