Whatever rising anger Eisman felt was offset by the man’s genial disposition. Not only did he not mind that Eisman took a dim view of his C.D.O.’s; he saw it as a basis for friendship. “Then he said something that blew my mind,” Eisman tells me. “He says, ‘I love guys like you who short my market. Without you, I don’t have anything to buy.’ ”

That’s when Eisman finally got it. Here he’d been making these side bets with Goldman Sachs and Deutsche Bank on the fate of the BBB tranche without fully understanding why those firms were so eager to make the bets. Now he saw. There weren’t enough Americans with shitty credit taking out loans to satisfy investors’ appetite for the end product. The firms used Eisman’s bet to synthesize more of them. Here, then, was the difference between fantasy finance and fantasy football: When a fantasy player drafts Peyton Manning, he doesn’t create a second Peyton Manning to inflate the league’s stats. But when Eisman bought a credit-default swap, he enabled Deutsche Bank to create another bond identical in every respect but one to the original. The only difference was that there was no actual homebuyer or borrower. The only assets backing the bonds were the side bets Eisman and others made with firms like Goldman Sachs. Eisman, in effect, was paying to Goldman the interest on a subprime mortgage. In fact, there was no mortgage at all. “They weren’t satisfied getting lots of unqualified borrowers to borrow money to buy a house they couldn’t afford,” Eisman says. “They were creating them out of whole cloth. One hundred times over! That’s why the losses are so much greater than the loans. But that’s when I realized they needed us to keep the machine running. I was like, This is allowed?”

This particular dinner was hosted by Deutsche Bank, whose head trader, Greg Lippman, was the fellow who had introduced Eisman to the subprime bond market. Eisman went and found Lippman, pointed back to his own dinner companion, and said, “I want to short him.” Lippman thought he was joking; he wasn’t. “Greg, I want to short his paper,” Eisman repeated. “Sight unseen.”

Eisman started out running a $60 million equity fund but was now short around $600 million of various ­subprime-related securities. In the spring of 2007, the market strengthened. But, says Eisman, “credit quality always gets better in March and April. And the reason it always gets better in March and April is that people get their tax refunds. You would think people in the securitization world would know this. We just thought that was moronic.”

He was already short the stocks of mortgage originators and the homebuilders. Now he took short positions in the rating agencies—“they were making 10 times more rating C.D.O.’s than they were rating G.M. bonds, and it was all going to end”—and, finally, the biggest Wall Street firms because of their exposure to C.D.O.’s. He wasn’t allowed to short Morgan Stanley because it owned a stake in his fund. But he shorted UBS, Lehman Brothers, and a few others. Not long after that, FrontPoint had a visit from Sanford C. Bernstein’s Brad Hintz, a prominent analyst who covered Wall Street firms. Hintz wanted to know what Eisman was up to. “We just shorted Merrill Lynch,” Eisman told him.

“Why?” asked Hintz.

“We have a simple thesis,” Eisman explained. “There is going to be a calamity, and whenever there is a calamity, Merrill is there.” When it came time to bankrupt Orange County with bad advice, Merrill was there. When the internet went bust, Merrill was there. Way back in the 1980s, when the first bond trader was let off his leash and lost hundreds of millions of dollars, Merrill was there to take the hit. That was Eisman’s logic—the logic of Wall Street’s pecking order. Goldman Sachs was the big kid who ran the games in this neighborhood. Merrill Lynch was the little fat kid assigned the least pleasant roles, just happy to be a part of things. The game, as Eisman saw it, was Crack the Whip. He assumed Merrill Lynch had taken its assigned place at the end of the chain.

There was only one thing that bothered Eisman, and it continued to trouble him as late as May 2007. “The thing we couldn’t figure out is: It’s so obvious. Why hasn’t everyone else figured out that the machine is done?” Eisman had long subscribed to Grant’s Interest Rate Observer, a newsletter famous in Wall Street circles and obscure outside them. Jim Grant, its editor, had been prophesying doom ever since the great debt cycle began, in the mid-1980s. In late 2006, he decided to investigate these things called C.D.O.’s. Or rather, he had asked his young assistant, Dan Gertner, a chemical engineer with an M.B.A., to see if he could understand them. Gertner went off with the documents that purported to explain C.D.O.’s to potential investors and for several days sweated and groaned and heaved and suffered. “Then he came back,” says Grant, “and said, ‘I can’t figure this thing out.’ And I said, ‘I think we have our story.’ ”