Martin H. Krieger, who was trained as a physicist at Columbia University, has been a Fellow at the Center for Advanced Study in the Behavioral Sciences and at the National Humanities Center. He is author of Marginalism and Discontinuity: Tools for the Crafts of Knowledge and Decision (1989), Constitutions of Matter: Mathematically Modeling the Most Everyday of Physical Phenomena (1996), and Doing Mathematics: Convention, Subject, Calculation, Analogy (2003). He is on the faculty of the University of Southern California, and has taught at Berkeley, Minnesota, MIT, and Michigan.