Janet Yellen is an American economist who has served as the Secretary of the Treasury since January 2021. She is the first woman to hold this position and previously served as the Chair of the Federal Reserve from 2014 to 2018. Yellen is known for her expertise in monetary policy and her focus on reducing unemployment and promoting economic growth. Before her roles in government, Yellen was a professor at University of California, Berkeley and held various positions in economic research. She has also worked at the Council of Economic Advisers and the Federal Reserve Bank of San Francisco. Yellen's work has significantly influenced U.S. economic policy.