I Love biographies. And what I love most are interesting failures. Uninterrupted success is dullsville. Defeat puts a sharper focus on the qualities that make us human.

That's why Abe Lincoln is so interesting: He failed in business and failed in a run for the Illinois legislature. He twice lost races for Congress and lost two races for the U.S. Senate. From that wreckage emerged one of our greatest presidents.

In the business world, the slumping economy puts defeat on everybody's minds. People lose jobs. Managers fail. Businesses close. Fear takes root.

Look at the headlines, tales of ousters and anguish: Jim Donald loses his job as chief executive of Starbucks. A string of CEOs arrive and leave at Tully's Coffee. Four thousand people lose their jobs at Sprint Nextel. Thousands more walk at Washington Mutual, doomed by lending misjudgments. A cancer drug doesn't work as hoped, so a quarter of the employees at Sonus Pharmaceuticals are shown the door. And for the biggest individual failure of the year, I nominate Jerome Kerviel, the 31-yearold trader at France's Société Générale whose botched trades cost the bank $7.2 billion.

Just as personal failure reveals character, business failure reveals the strength of our economic system, what economist Joseph Schumpeter calls the "creative destruction" of capitalism. Those who adapt after failure can be highly valued. "If I am given a choice between a guy who has failed a couple of times and a guy who is starting his first [business]," the venture capitalist John Doerr once said, "I will fund the guy who has failed."

Now, struggle and failure are different things. Struggle means you face and overcome challenges, but your survival isn't necessarily in doubt. Microsoft struggled with challenges from companies like IBM, WordPerfect and now Google, but no one seriously worries about the company's survival.

Failure means you are knocked down. Kaput. Busted. And it's no secret to friends and family.

So it's one thing to know it's going to be hard, but another thing to know you face ruin. That's the stunning part about businesses that bet the company. Certain industries are inherently risky. Restaurants. Venture capital. Even aerospace. Launching a new aircraft is so hideously expensive and complex that each time Boeing starts a new program, individual careers and the entire company can go on the line.

When I wrote a book years ago about Craig McCaw, I asked his brother, Bruce, how they could sleep with so much risk in the wireless industry. Simple, he said: Since we knew how to start businesses, we knew we could do it again.

I've never met Martin Tobias, and I don't know the inside story of his career challenges, but he's got that confidence. After six years at Microsoft, Tobias started a company that became Loudeye Technologies, which he took public in 2000. After a time, that company struggled and he left. He then joined a small biodiesel company, Imperium Renewables, as chief executive and helped it raise $113 million and borrow another $101 million. Last December, Tobias unexpectedly stepped down. The following month, Imperium cancelled its initial public offering. Tobias, at 44, has three careers behind him, and presumably personal wealth, but he's already moving on to new endeavors: joining a venture capital group, developing a building in Seattle, writing a personal blog (www.deepgreencrystals.com) and soliciting business plans. The guy doesn't quit. You have to admire that.

Confidence becomes delusion, of course, when you don't learn from failure. It's important to be honest with yourself. That's why I was so taken by one of Boeing's executives, Pat Shanahan, vice president and general manager of the 787 Dreamliner program.