What a Teacher and a Student Learned about Life While Corresponding about Math

David T. Kung in American Scientist:

Take a minute to think back a few years—okay, maybe a few more than that—to your high school days. Think past the awkward dances, the tortured relationships, the overhyped football games, to your high school math teachers. Who were they? What were their lives like? What did they do when they weren’t teaching you how to factor, what a logarithm is or how to take derivatives? What are they up to now?

Unlike many of us, Steven Strogatz can actually answer these questions, at least with regard to his high school calculus teacher, Don “Joff” Joffray. Strogatz shares those answers and much more in The Calculus of Friendship. Part biography, part autobiography and part off-the-beaten-path guide to calculus, this quick read details 30 years of correspondence between Strogatz (who is now Jacob Gould Schurman Professor of Applied Mathematics at Cornell University) and Joffray.

Calculus, Isaac Newton’s ingenious invention for modeling change mathematically, serves as both text and subtext for the letters that pass between Strogatz and Joff. Focusing almost exclusively on questions of mathematics, these brief notes frame the unlikely friendship of a teacher and his star student. With the precision of an award-winning mathematician and the clarity of a best-selling science author, Strogatz leads us on an excursion through some of the lesser-known mathematical sights—the ones usually reserved for the “members only” tour. All the while, we see the relationship between the two men gradually change as they slowly (and I do mean slowly) break down the walls that appropriately separate teacher from student.

More here.