Seth Klarman is worth listening to, especially when markets go mad.

Mr. Klarman is president of the Baupost Group, an investment firm in Boston that manages $22 billion. His three private partnerships have returned an annual average of around 19% since inception in 1983—and nearly 17% annually over the past decade, as stocks went nowhere.

To measure Mr. Klarman's importance as an investor, you need only see the value his rivals place upon his words. You could have earned at least a 20% average annual return since 1991—better than twice the performance of the market—merely by buying and holding Mr. Klarman's book, "Margin of Safety": Published that year at a cover price of $25, hard copies now fetch up to $2,400.

But the professorial Mr. Klarman speaks in public about as often as the Himalayan yeti. He made an exception last Tuesday, when I interviewed him in front of a standing-room-only crowd of 1,600 financial analysts at the CFA Institute annual meeting in Boston. He then made another exception, speaking with me over the phone later to clarify points that he feared had been misconstrued.

Mr. Klarman specializes in buying securities that nauseate other investors. As the credit crisis exploded, he put more than a third of his assets into high-yield bonds and mortgage-related securities. I asked him what he had meant, in a recent letter to his clients, when he compared the financial markets to a Hostess Twinkie. "There is no nutritional value," he said. "There is nothing natural in the markets. Everything is being manipulated by the government." He added, "I'm skeptical that the European bailout will work."