????Michael Mayo, the analyst who has never seemed afraid to criticize and cajole the world's most powerful banks, wants you to know that he's a rebel. It's the persona that he's cultivated in the press and with investors; and it's also at the heart of his new book, Exile on Wall Street, the title itself is a riff on the Rolling Stones' 18-track paean to sex, drugs, and rock 'n roll.

????Mayo, 48, convincingly shows himself to be pretty punk rock among sell side analysts. He called the bottom in bank stocks in 1994, and he was derided for it until the markets proved him right. He said to sell those very same stocks in 1999, a move that he asserts got him fired from Credit Suisse First Boston. (Fortune came to the same conclusion in a 2001 story about Mayo called "The Price of Being Right.") And long before the mortgage crisis revealed executives at the nation's largest banks to be some combination of cynical, morally bankrupt, or na?ve, Mayo was calling out Wall Street executives for cronyism, lavish pay, and mismanagement. As one might imagine, his work has not made him wildly popular with his employers, who have mostly been bank CEOs. In a short time he burned several jobs and now works as a banking analyst at the small firm CLSA, an affiliate of France's Credit Agricole Securities.

????Mayo explains that he comes from a family of non-conformists. His mom, who was raised in an Orthodox Jewish home, embraced yoga, divorced, and remarried all before Mayo was five. And his beloved stepfather was an outsider and a fighter who escaped Communist Romania, fought for Israel in 1948, and slept with a handgun by his bed for his whole life. Mayo wasn't armed with an Ivy League education or family connections as were so many of his contemporaries who were also seeking jobs in finance. And even after he had worked at firms including UBS, Lehman Brothers, and Credit Suisse, he never really fit in with the culture of Wall Street. At a party thrown at the summer house of a Lehman client in 1994, Mayo writes that he and his wife were fish out water in a sea of navy blue sport coats. "Jackie and I were used to the parties at Dewey Beach, where you showed up to parties in a bathing suit, and if you wanted to be a little dressy, you put a neon T-shirt over it," he recalls.