Photos: Seat of financial power: Federal Reserve chairs through the years

Janet L. Yellen takes over Feb. 1 as the first woman to chair the Federal Reserve as it tries to pull back a key stimulus program without derailing the recovery. Yellen, 67, a former UC Berkeley economist, has been the Fed’s vice chair since 2010, serving as a close ally of outgoing chair Ben S. Bernanke in the central bank’s unprecedented efforts to boost the economy after the Great Recession.