How did Marissa Mayer climb so far so fast?

This picture of Mayer–who is on the right, with her best friend from childhood, Abigail Garvey Wilson–offers a glimpse of where she came from. I talked with Abby, as well as dozens of other people Mayer grew up with–from her hometown of Wausau, Wisconsin, to Stanford University to Google to Yahoo , where she was recruited last July to turn around the troubled company.

Marissa Mayer: Ready to rumble at Yahoo is my profile of Mayer that appears in the new issue of Fortune. The profile tells you about her career credos: “Do things that you’re not quite ready to do. And surround yourself with the smartest people,” she says.

Another perspective, which I didn’t have room to include in the story, comes from Tom Stocky, a former Google employee who graduated from the highly regarded APM–associate product manager–program that Mayer created for rising stars there. “She goes beyond managing people to investing in people on a personal level,” Stocky told me. “That causes everyone on her team to work harder.”

Stocky, who is now a director of product management at Facebook , recalls Mayer once telling him: “Most people think of a career trajectory as a sloping line. Really, it’s a step function.” She went on to tell him: “When you’re ready to take the next step or take on more responsibility, you should start doing your job at the next level.”

If you do that, Mayer said, “The promotion will come naturally.”

Hmm, Mayer took her own advice. Now at Yahoo, where she is the fifth CEO in five years–caring for restless investors as well as a new baby boy–she’ll definitely be working at the next level.