Nobel Prize-winning free-market proponent and economist Milton Friedman has died as the age of 94, his family foundation said today.

Friedman passed away in San Francisco. The cause of death was reported to be heart failure.

He won the Nobel Prize in 1976 for “his achievements in the field of consumption analysis, monetary history and theory, and for his demonstration of the complexity of stabilization policy.”

In more than a dozen books, a magazine column and a TV show on PBS, Friedman championed individual freedom in economics and politics. The longtime University of Chicago professor pioneered a school of thought that became known as the Chicago school of economics.

His theory of monetarism, adopted in part by the administrations of presidents Richard Nixon, Gerald Ford and Ronald Reagan, opposed the traditional Keynesian economics that had dominated U.S. policy since the New Deal. He was a member of Reagan’s Economic Policy Advisory Board.

After earning a doctorate from Columbia University in 1946, Friedman taught at the University of Chicago until 1976. He became a senior research fellow at Stanford University’s Hoover Institute in 1977.

“Milton’s passion for freedom and liberty has influenced more lives than he ever could possibly know,” said Gordon St. Angelo, the president and CEO of the Milton and Rose D. Friedman Foundation, in a statement posted on the foundation’s website.

“His writings and ideas have transformed the minds of U.S. Presidents, world leaders, entrepreneurs and freshmen economic majors alike. The loss of his passion, incisive mind and dedication to freedom are all national treasures that we mourn for today,” St. Angelo said.