But the profit was only the beginning of the story. In Hong Kong, the Securities and Futures Commission sued Left for “false and misleading claims,” a failure to adequately support his accusations with evidence. The judge found him guilty and barred him from trading on the Chinese markets for five years. (Left objects to the decision on free-speech grounds and is appealing the ruling.) He refused to give up the name of his fact-checker. As to the identity of the anonymous sender, there was nothing to give up: Left had no idea who it was, except someone who almost certainly had a short position in Evergrande and made a fortune off the publication without the hassle of appearing in court. That was the point of using physical paper. Courts can subpoena your emails, but good luck tracing the mail backward from your gated community in Beverly Hills.

As careful as Left must be to fact-check, hesitation hurts, too. If you’re slow, other shorts can scoop you, which is exactly what happened with the online postage seller: A competitor had published a version of Left’s thesis on a finance blog, and the stock’s price had fallen too far to short. Back at his home office, Left tried to work, but the atmosphere was lazy, diffuse. He called a source. “What do you think?” he said, asking about the postage stock. “Will it bounce?” The source replied that it would not.

Left squinted at CNBC. Then he roared. It began as a self-mocking “Why me?” exasperation but expanded into something more unhindered, a primal American shriek. “UugghHHAAAAHHHHHHHHHHH​HHHHHHHHHH.”

When he was through, he said, almost to himself, “There has got to be an easier way to make money.”

There is, of course. Be born to wealthy parents, attend Harvard, get a job at Goldman Sachs. Left was born in Detroit and raised in Coral Springs, Fla., the second son of parents who divorced when he was 5, after which his father moved back to Michigan and out of Andrew’s life. His mother, Rhoda Left Black, scraped together an income. During the day, she was an office manager at the public school. In the evening, she gave Hebrew lessons. She sold encyclopedias door to door, then eel-skin purses. “Anything I could do that was legal and moral and made a buck,” Black, now 73, told me. When Left asked her why she didn’t leave her secretarial job for something better, she said, “We need the insurance.” He had no idea what that meant. At the grocery store, they found the dented cans to get the discount at the register.

Recognizing his ability to dazzle an audience at a young age, Black wanted her son to become a lawyer or a rabbi. Instead, he was accepted at Northeastern and chose political science. Boston confronted him for the first time with people who had always had money. They knew that Beverly Hills was an actual place in California, not a made-up city on TV. They wore black. They didn’t drink Bartles & Jaymes.

After graduating in 1993, Left responded to a newspaper ad from an outfit called the Universal Commodity Corporation, offering $100,000 a year for work in what the advertiser knew not to call a boiler room. Boiler rooms are cold-call centers for stocks, where men in bare-walled offices put the screws on unsophisticated marks. (As in: “This is a once-in-a-lifetime opportunity, Mrs. Jones. I’d hate to see your husband miss out.”) Roberta Karmel, a former Securities and Exchange Commission regulator who policed the Long Island boiler rooms in the 1980s, described to me a typical employee. “He tended to go to lesser schools for college,” she said. “Or not go to college at all. And a lot of them were kind of scrappy personalities who thought: Well, I’m just as smart as the people at the white-shoe firms. I can make a lot of money, too.”

Maybe — if you’re good at it. Left was not. He would meander off script and lose the sale. He quit after nine months, ejecting himself into the mid-’90s froth, where there was very little oversight and, almost everywhere you looked, a thick layer of scumminess. These were the years when the future “Wolf of Wall Street” author Jordan Belfort ran a brokerage firm on Long Island, taking small companies public. Left started flipping penny-stock I.P.O.s, including Belfort’s — he would call up the “bucket shops,” or storefront stock exchanges, ask for shares before a company went public and then sell them later at a profit.