Andrea diSessa is Evelyn Lois Corey Professor of Cognition and Development at the University of California, Berkeley. He received his AB in physics from Princeton University and his PhD, also in physics, from the Massachusetts Institute of Technology. His research focuses on conceptual change, particularly the nature and role of intuitive knowledge, and on transformative possibilities of technology use in education. diSessa was twice a Fellow of the Center for Advanced Study in the Behavioral Sciences and received the Australian Council for Education Research/Australian Telecom Sunrise Fellowship. His publications include Turtle Geometry: The Computer as a Medium for Exploring Mathematics (with Harold Abelson),Toward an Epistemology of Physics (Cognition and Instruction monograph), Computers and Exploratory Learning (with Celia Hoyles and Richard Noss), and Changing Minds: Computers, Learning, and Literacy. He has been active as an editor, executive editor, and on the editorial boards of a number of journals, including currently serving as editor-in-chief of Cognition and Instruction.