Halbert Carl Christofferson was born on January 5, 1894, in the small, farming community of Racine, Minnesota, near Rochester.  He graduated from high school with honors, after attending for only three years, and began teaching in a country school.  His summers were spent working on a farm and in a machine shop.  He graduated Phi Beta Kappa with an A.B. degree from the University of Minnesota in just 3½ years and continued his career as a teacher, principal, and superintendent of schools in several Minnesota communities.

In 1923 Christofferson earned a Master of Arts degree from the University of Chicago and accepted a position as head of the Mathematics Department at Wisconsin State Teachers College in Oshkosh.  Five years later he was hired as Professor of Mathematics at Miami University in Oxford, Ohio.  In 1935, after earning a Ph.D. from Columbia, he assumed the additional duties of Director of Secondary Education.  He held a joint appointment in the Department of Mathematics and the School of Education until his retirement in 1961. 

Dr. Christofferson’s best known publication is Geometry Professionalized for Teachers, based on his 1933 doctoral dissertation at Columbia.  He was an early advocate of inquiry methods of teaching mathematics.  He also wrote a number of mathematics workbooks and journal articles, and he was the mathematics editor of School Science and Mathematics from 1942-45.  Dr. Christofferson served on the board of directors of the National Council of Teachers of Mathematics from 1934-38, followed by a term as NCTM President (1938-40).  He was a co-founder of the Ohio Council of Teachers of Mathematics in 1950, and he served as President of  OCTM from 1952-54.

Dr. Christofferson was active in Oxford community life, serving as Chair of the Community Chest, President of the Kiwanis Club, an elder and Sunday school superintendent in the Presbyterian Church, and a member of the Masonic Lodge.  He contributed generously to Miami University, including endowments to establish scholarships and prizes for future mathematics teachers.  He died at Rochester, Minnesota, on June 4, 1973.