Professor Henle's fields of interest include: set theory, logic, nonstandard analysis, mathematics education, philosophy of mathematics, music and food.
Henle was a Peace Corps volunteer in the Philippines and has made research trips to England and Venezuela. His current research takes him to to flashing lights, sticky bounces, historic camera angles, economic inequality and tiling planes with squares. His latest book, The Proof and the Pudding, was published in May by Princeton University Press--- http://press.princeton.edu/titles/10436.html.
David P. Robbins Prize of the Mathematical Association of America (with son, Fred Henle)