Isaac Kaufmann Funk 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, who continued his father's authorship of Word Power until 2003. Funk & Wagnalls Company published The Literary Digest, The Standard Dictionary of the English Language, and Funk & Wagnalls Standard Encyclopedia.

Funk & Wagnalls was an American publisher known for its reference works, including A Standard Dictionary of the English Language, and the Funk & Wagnalls Standard Encyclopedia.