Martin Ralph DeHaan (March 23, 1891 - December 13, 1965) was an American Bible teacher, the founder of the Radio Bible Class, and the co-editor of a monthly devotional guide Our Daily Bread.
M. R. DeHaan was born in Zeeland, Michigan to Reitze and Johanna Rozema DeHaan, emigrants from the Netherlands. After graduating from Zeeland High School in 1908, he attended Hope College in Holland, Michigan, for a year before attending and graduating from the University of Illinois College of Medicine in Chicago in 1914.
DeHaan established a country practice in Byron Center, Michigan, about fourteen miles east of his home town. The practice frequently pushed him near exhaustion, at no time more so than during the 1918 flu pandemic, when for five days he never took off his clothes. He enjoyed the work of a physician, especially when fast thinking allowed him to save or improve lives. He even diagnosed his own mother's diabetes by looking at her eyes and was able to prescribe insulin, only recently invented.
Although he had been reared in a devout home and was a regular church goer, DeHaan acquired "a rather stout appetite for alcohol" during his years of medical practice. In October 1921 he suffered a violent reaction to an injection of horse serum and hovered in critical condition at a Grand Rapids hospital, where he later wrote he "was born again of the Spirit." DeHaan said he had told God, "Spare my life and I'll serve You." Afterward, when a grateful patient presented DeHaan with a bottle of liquor, he emptied it down the drain. In the early spring of 1922, he returned home one day from house calls and told his wife, "I can't go on any longer. This is it!" He sold his medical practice, home, and office equipment and entered Western Theological Seminary in Holland, Michigan, practicing a bit of medicine on the side to pay the bills.