Herbert Dulle taught mathematics, specifically calculus, at Springfield High in Springfield, Illinois for 25 years. His published obituary is here. What it doesn't say is that he also completed all of the requirements for the PhD except the dissertation taking summer classes at the University of Montana.

He introduced many students at Springfield High to computers in his spare time. In the 1970's he convinced administrators to allow access to a school district IBM 1401 once or twice a week where we learned FORTRAN. He was also involved with the PLATO terminal installed at Springfield High.

His calculus class used a book that is considered a graduate-level calculus text, Johnson & Kiokemeister's Calculus with Analytic Geometry, fourth edition. I am told that such a class should be called advanced calculus. It is a path to rigorous and clear thinking.

My notes from the class transcribed to LaTeX for distribution are available here and formatted for double-sided printing here.

My hope is that another teacher will be inspired to give the same sort of experience to a group of enthusiastic high school students.