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.