Isaac Kaufmann Funk (September 10, 1839 – April 4, 1912) was an American Lutheran minister, editor, lexicographer, publisher, and spelling reformer. He was the co-founder of Funk & Wagnalls Company, the father of author Wilfred J. Funk, and the grandfather of author Peter Funk. Wilfred Funk founded his own publishing company "Wilfred Funk, Inc.", and wrote the "Word Power" feature in Reader's Digest from 1945. The feature was carried on by Peter Funk from 1962-1998.