Meg Whitman is the most interesting person in American politics and, potentially, a formidable Republican leader at the national level. At age 52 and a year after stepping down as CEO of eBay, she's running for governor of California. Like Ronald Reagan, she's a well-known star from another field--the corporate world in Whitman's case--who has entered California politics at the top and now intends to leapfrog an entire generation of ambitious political strivers.

Similarity to Reagan isn't what makes Whitman exceptional. Nor does the possibility she might copy a fellow billionaire, New York mayor Michael Bloomberg, and dip into her own fortune to win high office. Gobs of personal money in a campaign rarely elevates a candidate and never guarantees success. Her only prior role in politics was as an adviser to two losing presidential candidates in 2008, first Mitt Romney, then John McCain. Yet she's not entirely a novice. "Business has always been my passion," Whitman says. "But I've always followed politics closely."

That's fine, but what distinguishes Meg Whitman and makes her a fascinating political figure is one thing: eBay. Her decade as CEO of eBay, one of the most successful Internet startups ever, is the foundation of her campaign. "My philosophy of government is almost entirely driven by my 10 years at eBay," Whitman told me. Her philosophy is not new. Her foremost lesson from eBay is that individuals with little or no capital will thrive as entrepreneurs when offered unrestricted opportunity, an efficient market, a level field playing field, and low costs. Now Whitman would apply that lesson--and many others from eBay--to California in the form of streamlined government, fewer bureaucrats, deregulation, less spending, and lower taxes.

Her years at eBay did another thing for Whitman. They made her a celebrity known to millions simply as Meg. Lucky for her, an attempt in her first corporate job at Procter & Gamble to be called Margaret quickly failed. Margaret Whitman? In politics, Meg works better. At eBay, she developed a likable, if not exactly charismatic, public personality. And as eBay flourished, she became a favorite of business journalists. Fortune named her the most powerful woman in business in America in 2004 and 2005. When she jumped into the governor's race, Fortune put Whitman on the cover, standing beside a horse.

EBay is an online auction and swap meet that began in 1995 as a marketplace for collectibles such as PEZ dispensers. (A collection of PEZ dispensers, assembled by the wife of eBay founder Pierre Omidyar, is on display at eBay headquarters in San Jose, California.) Now buyers and sellers deal in everything from baby clothes to a Gulfstream II jet that auctioned for $4.9 million. In 2001, Bob Dylan's boyhood home in Minnesota was sold on eBay for $94,600.

Contacted in 1997 about the job of eBay chief executive, Whitman politely refused to meet with Omidyar in California. At the time, she lived outside Boston and ran the division of Hasbro, Inc., that markets Mr. Potato Head and other toys. She had moved east in 1992 when her husband, Griff Harsh, a brain surgeon, became head of neuro-surgery at Massachusetts General Hospital. (Whitman is her maiden name.) Persuaded a few months later by a Silicon Valley headhunter to fly to California, she spent a day at eBay. One day was sufficient. She called her husband that evening and announced she was ready to uproot their family (two sons) and move to California. When she arrived in 1998, eBay had 30 employees, $4 million in revenues, and 300,000 registered users. When she left in 2008, it had 15,000 employees, $7.7 billion in revenues, and nearly 300 million registered users worldwide, more than 12 million of them in California. From 2002 to 2004, eBay was the fastest growing e-commerce company in the world.