John Givan Davis Mack (September 5, 1867 – February 24, 1924) was a professor of engineering at the University of Wisconsin.

John Givan Davis Mack was born in Terre Haute, Indiana on September 5, 1867.

[4] In 1898 he registered the patent of the Mack Improved Mannheim Simplex Slide Rule, which he then assigned to Eugene Dietzgen who put the slide rule into production.

[5] He died from a heart attack in Madison on February 24, 1924.

[1][2] Upon his death, a portrait of Professor Mack was given to the Wisconsin Historical Society Library to mark over thirty years involvement with the university.