Henzinger, now 36, went on to earn her doctorate in computer science from Princeton University. But it was while teaching courses on her beloved algorithms at Cornell University when she had a flash. "I realized that efficient algorithms were fun but not very useful to the world anymore," she says. Soon after, she left the academy and turned her attention to something that would be: Web search technology. Now, as director of research for Google, the Web’s hottest search engine, Henzinger stands at the cutting edge of what many consider the Web’s most useful technology.

Her colleagues in the tight-knit field of Web search technology consider Henzinger a pioneer.

"Monika was involved in Web search research from the start, even before Google was founded," says Bay-Wei Chang, a senior research scientist at Google. "She comes up with great ideas and then goes off and thinks them through."

Henzinger traces her early interest in math and science to a magazine article on the Martian atmosphere. "I thought that was the coolest thing in the world," she says. Thereafter, math and physics teachers gave her problems to work on outside of class. Her career goal at the time? Mission specialist on a space shuttle.

Years later, her feet firmly planted in Silicon Valley, Henzinger turned her attention to Web information retrieval research at the Digital Systems Research Center in Palo Alto, Calif. There, she met two Stanford grad students whose research piqued her interest. Instead of ranking webpages by how many times a key word appears (as other search engines do), they chose to rank them by the popularity and relevance of each page according to the Web’s vast link structure. For example, they interpreted a link from page A to page B as a vote by page A for page B. The more votes, the higher the ranking. These two students, Sergey Brin and Larry Page, went on to found Google in 1998, and a year later Henzinger started up the company’s research department. Google now processes more than 150 million searches a day, or about 1,800 searches a second, in 74 languages in 32 countries. Henzinger’s algorithms have a lot to do with that success.