Michael Dell, Chairman and CEO of Dell Computer, leads FORTUNE's inaugural list of "America's 40 Richest Under Forty," the first such listing to focus on the Internet era's unprecedented intersection between youth, technology and riches. The most prominent college dropout on the list, Dell is also the richest by far with estimated assets of $21.49 billion-all of which he amassed by the ripe old age of 34. Internet cover boy Jeff Bezos, 35, Chairman, CEO and President of Amazon.com, is the second wealthiest American under 40 with an estimated wealth of $5.74 billion, while Gateway's 36 year-old Chairman and CEO Ted Waitt comes in close behind at No. 3 with $5.44 billion to his name. eBay Chairman Pierre Omidyar's position at No. 4 ($3.69 billion) indicates how valuable a good idea-in this case selling Pez dispensers on the World Wide Web-can be in the Internet age. The 33-year-old David Filo, Chief Yahoo! of Yahoo!, comes in at No. 5 with $3.12 billion and, at the tender age of 30, the other Chief Yahoo! Jerry Yang still has time to catch up to his colleague from his position at No. 6 on the list with $3.05 billion. "America's 40 Richest Under 40" appears in the September 27 issue of FORTUNE, and is available on www.fortune.com.

While FORTUNE's list of the hyper-rich was dominated by Internet pioneers, among the notable exceptions to that rule were basketball icon Michael Jordan with $357 million to his world-renowned brand name (No. 29), and No Limit Enterprises CEO and rapper Master P (No. 28, $361 million), who built a hugely successful independent record label and expanded it into films, toys, shoes, and sports management (For the full story, see Roy S. Johnson's "Diamond in the Rough," on page 166 in the Sept. 27 issue of FORTUNE). Also notable was the absence of women: eBay's Meg Whitman would have ranked No. 14 with an estimated worth of $699 million, but she's 42; and Kim Polese of Marimba is comparatively poor with only $70 million.

Indicating that a prestigious university education may not be the quickest route to riches, 11 of the "40 Under 40" list were dropouts, while only 5 percent of the list claimed Stanford or an Ivy League college as their alma mater.

Consistent with the counterintuitive math typically associated with IPO riches, the Internet executives on the list had an average net worth of $1.5 billion, while average annual earnings for their companies were abysmally low at minus $36 million.

A number of other companies spread the Internet rewards among more than one employee: Inktomi had both its Chief Scientist Eric Brewer with $454 million (No. 19) and CTO Paul Gauthier with $418 million (No. 21); Sapient both Co-CEOs Jerry Greenberg (No. 22 at $413 million) and Stuart Moore (No. 23, $404 million); and CNET both its Executive VP and COO Shelby Bonnie (No. 24, $403 million), and Chairman and CEO, Halsey Minor (No. 31 with $354.9 million).

In a sign of what Internet wealth can buy these days, FORTUNE calculated that Michael Dell could buy computers for every high school student in the country with his wealth ($13.5 billion); Jeff Bezos could wipe out the national debt of Honduras ($4.9 billion); Scott Blum could buy each of his fellow 40 a GulfStream Jet ($1.6 billion); Jerry Greenberg's tax on the Sapient stock he sold could have bought an island in Fiji ($10 million).

To help explain how these 40 made it so far so fast, Melanie Warner's introductory piece to "America's Richest 40 Under40" profiles four of the cyber titans who epitomize how the new economy has re-routed the road to riches-and the unique personality traits that brought them there. According to Warner, all of the four multi-millionaires profiled-Henry Nicholas III of Broadcom (No. 7), Jeffrey Arnold of WebMD (No. 33) and Eric Brewer and Paul Gauthier of Inktomi (Nos. 19 and 21, respectively)-are marked by the "missionary zeal" with which they approach their work, as well as the belief that what they do is changing the world.

And, in a provocative look at the less attractive underbelly of all this Internet glory, Eryn Brown's accompanying story, "Valley of the Dollars," tells how a money-obsessed culture is transforming Silicon Valley. As Brown reports, Internet wealth "has created a community where grossly skewed expectations, measured in terms of dollars, define personal success." Brown continues, "Intangible benefits-having a fun job, creating exciting technology-don't stand on their own anymore, no matter how often people say, 'It's not about the money.' It's all about the money."

To compile the list of "America's 40 Richest Under 40," FORTUNE sifted through SEC filings and insider-trading records, and kept close watch on market volatility (If Amazon lost a point, Jeff Bezos lost $60 million)-choosing August 13 as the last day to calculate wealth. To assess the net worth of individuals not tied to public companies, FORTUNE enlisted the aid of investment bank Houlihan Lokey Howard & Zukin to conduct valuations of private companies; to determine what hedge fund managers and venture capitalists make from the money they manage, FORTUNE interviewed industry insiders, bankers, analysts, and accountants, and then created formulas to calculate their personal fortunes. For a reality check, everybody on the list was charged capital gains taxes on insider trades, cash deals, and exercisable options. Unexercisable options were excluded altogether.