Cool Companies 2004 How do you recognize cool? You know it when you see it--that's what we've maintained since launching the first list of Cool Companies in 1993. In the early 1990s, cool tech companies were those generating buzz; in the late '90s, we, like everyone, focused on youth. And this year? It's back to basics.
By Julie Schlosser

(FORTUNE Magazine) – A few of the young companies featured ahead are making their mark by taking on basic needs like health and security. Quantum Dot turns cells into tiny Lite-Brites, aiding scientists (for more, see the following story, "Is Nanotech Ready for Its Close-Up?"); PhageTech is finding ways to make medicine by mimicking natural bacteria-killers called bacteriophages. iPass software allows companies to use Wi-Fi without fear, while Securify has helped keep the U.S. battlefield network in Iraq open to the good guys but closed to the bad. And what could be more basic than the desire to get rid of body odor? Check out Noble Fiber's efforts to do so using silver and cloth.

Unlike the late 1990s, Red Bull--fueled twentysomethings no longer dominate Cool Companies. The starkest example: Paul MacCready, a 78-year-old aerospace legend who designs drone planes and is currently launching an airborne cell tower.

To build the list, we screened more than 100 candidates submitted by venture capitalists, entrepreneurs, and other sources. Of course, if you're looking to invest, it's cooleat emptor: There's no way to know for sure which firms will be able to turn cachet into cash. Still, it'll be fun watching them all try. --Julie Schlosser