The Snowball, the first authorized biography of Warren Buffett, has been one of the most eagerly anticipated business books of the year. Published on Monday, the book is particularly timely because of Buffett's role in the credit crisis now roiling Wall Street, including Wednesday's purchase of a stake in G.E.

A team of Portfolio.com writers, continuing today with deputy news editor Jeffrey Cane, are reviewing the book in sections this week, and will be commenting on each other's reviews (here are parts one, two, three, and four in case you missed them). Readers are invited to add their thoughts in the Comments section.

In these tumultuous times for the markets, Warren Buffett can appear as a lone rescuer holding aloft a beacon and striding through the storm with calm and confidence.

His recent investments in Goldman Sachs and General Electric have only enhanced his reputation as an extraordinarily savvy investor and as an elder statesman of the financial world.

Yet it is worth keeping in mind that this has not always been the case. 

The sixth and final part of The Snowball, entitled "Claim Checks," begins at the start of the new century, when Buffett's reputation was beginning to dim a bit.

He had steered clear of technology stocks at a time when the internet boom was producing a rally of breathtaking gains for other investors. A recent acquisition, the reinsurer General Re, was a problem child almost from the start, while a major holding, Coca-Cola, was stumbling under Douglas Daft. And a deal to acquire Clayton Homes, a leader in manufacturing housing, seemed to bring nothing but trouble.

Buffett, it appeared, was losing his game.

The decade was also a very difficult one for Buffett personally. His close friend, Katharine Graham, died in 2001, while his first wife, the beloved Susie, died in 2004. And Buffett had his own intimations of mortality as he entered his 70s, suffering from kidney stones and benign polyps in his colon. ("I went into the hospital with a colon, but I came out with a semicolon," Buffett would later say.)

But the book is sketchy on the biggest crisis at Berkshire Hathaway during the decade: a deal that threatened to tarnish his shining reputation for integrity for the first time.

A 2000 finite reinsurance transaction between General Re and American International Group was done to artificially inflate A.I.G.'s premium reserves, investigators found. Earlier this year, five former executives, one from A.I.G. and four from General Re, were convicted of fraud and conspiracy charges stemming from that transaction.

Buffett was never accused of any wrongdoing. Yet it must have pained him to have impropriety in such close proximity. He was a long-time business associate of the chief executive of A.I.G. at the time, Hank Greenberg, who continues to be dogged by the transaction. Prosecutors identified Greenberg, who resigned as chief executive of A.I.G. amid accounting investigations in 2004, as an unindicted co-conspirator in the General Re case.

Buffett rarely fires managers. Earlier this year, however, the chief executive of General Re, Joseph Brandon, was ousted, reportedly as a result of pressure from federal prosecutors.

In The Snowball we don't learn anything about how Buffett dealt with the pressures and stress of the General Re investigations. To be fair, the hands of the author, Alice Schroeder, were tied: She notes that she testified in the criminal case in her capacity as a former insurance industry analyst, and is under subpoena in the lawsuit that was brought by Eliot Spitzer, then the New York attorney general, against Greenberg.

Still, it is a big hole that future biographies will have to fill.

By the end of the book and 2008, however, Buffett is vindicated. He had overcome personal losses and any lingering doubts about his investing style or leadership.

The bubble in tech stocks had burst, as he had warned at Sun Valley in 1999. Shares of Coca-Cola recovered under a new chief executive, Neville Isdell, and even General Re straightened out.

More important, the evolution of Buffett into wise old man and celebrity was complete by 2008.

This is a phenomena that deserves closer examination.

Schroeder does capture Buffett's rock-star aura, especially in describing the Woodstock of capitalism that takes place every year at the Berkshire Hathaway shareholders meeting in Omaha. (For me, the most surprising revelation in the book is that one year a number of attendees engaged in pirate capitalism, shoplifting various Berkshire Hathaway products on display.)

Buffett even gets to hobnob with rock stars, like Bono of U2 ("U2's music doesn't blow me away," Buffett tells the author. "What interests me is that Bono splits the revenue of U2 among four people absolutely equally.")

But Schroeder fails to dig deeper to explain why Buffett strikes a chord in such a way that other celebrity C.E.O.'s do not. At the same time, many who eat up what Buffett has to say seem to do so without carefully following his principles or putting in a fraction of the focus and work that he does.

The "less flattering" reason, according to Schroeder:

"What people paid attention to was simply how rich he was. Indeed, as much as he wanted them to study his model, Buffett sometimes inadvertently discouraged it; he also wanted people to believe that he tap-danced into work every day and had fun."

It is difficult at times to get past the incredible wealth and the shtick—the Cherry Cokes and corny jokes and aw-shucks air that seem like throwbacks to a black-and-white sitcom from the 1950s (Warren Knows Best, perhaps?).

But that persona has obscured what is Warren Buffett's most important legacy. During an era when Davos attendees babble about globalization, eyeballs, or structured investments, Buffett has been one of the few executives who have spoken about the responsibility of the wealthy to society.

He has protested against Republican efforts to eliminate the estate tax, and spoken out about a tax system that is unfairly skewed to benefit the ultra-wealthy. In philanthropy, he has eschewed ego and decided to give the bulk of his vast wealth to the Bill & Melinda Gates Foundation.

"All along, I've felt that the money was just claim checks that should go back into society," Buffett says in The Snowball.

While other C.E.O.'s have put shareholders' money at risk to chase the latest fad while awarding themselves huge pay packages, Buffett has long espoused a sensible conservatism.

He opposed the awarding of stock options at a time when Silicon Valley insisted they were essential to running a tech company.

And Buffett warned against the use of derivatives, calling them "financial weapons of mass destruction" when Alan Greenspan and others were hailing them for helping to spread risk.

The Snowball ends with the current financial crisis erupting. While the book does not make this argument explicitly, if there had more than one Warren Buffett in the last decade, we might not be in such dire straits today.