Scion of a family that owned The Des Moines Register, started Look magazine and came to dominate the newspaper business in Minneapolis for more than half a century, Mr. Cowles (rhymes with bowls) succeeded his father in 1961 as the editor of two Minneapolis papers, the morning Tribune and the evening Star. He became president and chief executive of The Minneapolis Star and Tribune Company (later renamed Cowles Media Company) in 1968. In 1982, the company merged The Star and The Tribune and cut its work force, prompting the editor of the merged papers to quit in protest. Mr. Cowles subsequently fired the publisher and assumed the role himself. But just a few months later, in early 1983, the board of Cowles Media, which included his sister and two cousins, dismissed him as publisher and head of the company as well. He remained on the board until 1984 and into the 1990s continued to control a substantial percentage of company stock through his management of a family trust. Cowles Media was sold to the McClatchy Company in 1998. Mr. Cowles was born on May 27, 1929, in Des Moines, Iowa, where his grandfather, Gardner Cowles, had been publisher of The Des Moines Register since 1903. His father, John, and his uncle Gardner Cowles Jr., known as Mike, founded Look magazine. John Cowles Sr. bought The Minneapolis Star in 1935 and moved his family to Minneapolis in 1938. Besides his son John III, known as Jay, Mr. Cowles is survived by his wife, the former Jane Sage Fuller, who is known as Sage Fuller Cowles and whom he married in 1952; another son, Charles; a daughter, Jane Sage Cowles; a stepdaughter, Tessa Flores; a sister, Sarah Cowles Doering; a brother, Russell; 10 grandchildren and two great-grandchildren.