In his post-trading life, Cramer continued writing about the stock market for TheStreet.com, a financial Web site he founded with Peretz, and in New York magazine and various other publications. In 2005 he started “Mad Money,” a show whose premise is that individual investors who do their homework and follow Cramer’s coaching can make money in the stock market.

The show was an immediate hit, in large part because of Cramer’s showmanship. He used props and sound effects to deliver his message, and bounced around the studio wearing sombreros and churning meat grinders, delivering information in a rapid-fire, digression-rich patter of high certainty. Cramer has no apologies for his on-air high jinks. “Business isn’t inherently entertaining,” he says. “A show that spends all its time comparing the valuation of the Swiss franc to the yen is a show that is canceled.”

On Valentine’s Day, Cramer and I went to a Nets-Spurs game at the Prudential Center in Newark. Cramer is a sports nut, and while his favorite teams are in Philadelphia, he was happy to cheer on the only basketball team in his adopted state. As we entered the arena, the sparse crowd began to stir. Fans, mostly younger guys, hollered out his name or “booyah!” one of his signature expressions. As we passed, some asked about specific stocks. “Good buy under 30,” he replied without breaking stride, or “only if you don’t have other energy stocks in your portfolio.”

As soon as we were seated, a representative of the Nets came by and invited us to move down to the floor. Nearby fans greeted him with pats on the back and more “booyahs.” Several asked for autographs. At halftime, WFAN interviewed him about the future of the franchise, and he accommodatingly taped a TV promo for the Nets.

Cramer picks stocks on the air, but he is not allowed to own any (the exceptions are shares of TheStreet.com, General Electric, CNBC’s old parent company and Comcast, its new parent company). He runs a charitable portfolio, Action Alerts Plus, which is governed by a trust and is open to public scrutiny. He can’t trade a stock he mentions on the air for at least five business days, and he must hold whatever he buys for at least 30 days. These rules make it impossible for him to engage in the hyperaggressive buying and selling of his hedge-fund days. Still, most years the Action Alerts Plus portfolio has beaten the S.&P. 500.

Cramer’s flamboyance and cockiness make him an easy target. Some maintain that it is simply impossible for any human to recommend as many stocks as he does (Barron’s, in 2007, put the number at 7,000 a year) and know what he is talking about. Barron’s conceded that Cramer’s advice was “generally smart, his knowledge of individual stocks amazingly detailed” but calculated that his on-air picks trailed the market. This is debatable, since Cramer doesn’t give equal weight to all his recommendations and doesn’t normally tell people when to sell.

But the more damning criticism of Cramer comes from Wall Street professionals who know how much expertise it takes to make money trading stocks. Amateurs, in their view, don’t stand a chance, and Cramer is merely egging them on. “Cramer induces his viewers to do things that are bad for them,” says David Swensen, who manages Yale University’s endowment. “He’s smart enough to know what he’s doing. ‘Mad Money’ delivers a very dangerous message — that individual investors can beat the market with momentum-driven, high-octane trading strategies. There are individuals who do beat the market, but their number is vanishingly small. Cramer is a master manipulator. He has absolutely no accountability. This is serious business; people’s retirements are at stake.”