Joan Countryman is assistant head for academic planning at Germantown Friends School in Philadelphia, where she has taught mathematics since 1970, and is a lecturer at the Graduate School of Education, University of Pennsylvania. Since 1985 she has worked with the Woodrow Wilson National Fellowship Foundation as a master teacher in a program offering summer institutes for secondary mathematics teachers. Joan has lectured extensively on new trends in elementary and secondary mathematics education, on gender and mathematics, and on the use of writing in mathematics classes. Her approach to teaching and learning mathematics is described by William Zinsser in a chapter of book, Writing to Learn.