Marissa Mayer

President and CEO, Yahoo The Google veteran (she was its 20th employee and first female engineer) received a call from Spencer Stuart über-recruiter Jim Citrin in June, dangling the top job at Yahoo. The move was risky; Yahoo's notoriously fickle board has named four CEOs in five years. But after 13 years at Google, most recently steering its local and map business, Mayer jumped at the promotion, ) notwithstanding the expected October arrival of her first baby (a son, born Sept. 30). Mayer's product development chops -- Google's iconic search page design is said to be her brainchild -- provide hope for the struggling Yahoo, which needs serious help growing revenue -- and its stock price. First move: Free lunch for everyone at Yahoo's Silicon Valley office. --Colleen LeaheyPhoto: Martin Klimek/Corbis