Although it is necessary to infuse courses and curricula with modern content, what is even more important is to give students the tools they will need in order to use, understand, and even make mathematics that does not yet exist. A curriculum organized around habits of mind tries to close the gap between what the users and makers of mathematics do and what they say (Cuoco, Goldenberg, and Mark 1996, p. 376).
E. Paul Goldenberg, pgoldenberg@edc.org, has taught second grade (self contained) through middle school (hardly contained at all) through high school and graduate school (mathematics and psychology for education). He is currently a Distinguished Scholar in mathematics education at Education Development Center (EDC) in Newton, Massachusetts, and spends much of his time developing curriculum for grades K–12.