Diane Ravitch , former Assistant Secretary of Educational Research and Improvement at the U.S. Department of Education, is the author of numerous books, including The Language Police: How Pressure Groups Restrict What Students Learn (Knopf, 2003), Left Back: A Century of Battles over School Reform (Simon & Schuster, 2001), and National Standards in American Education: A Citizen's Guide (Brookings, 1995).