In May, she completed her biggest move yet with the $6.4 billion acquisition of Danish food ingredient producer Danisco, shifting the chemical company more toward food and nutrition. Analysts credit her with DuPont's turnaround in the stock market: Shares have returned 99%, vs. 37% for the S&P, since she took over in 2009.
Boardroom battles and power plays shaped this year's U.S. list, which boasts eight new faces and -- surprise! -- a new No. 1.
