Book excerpt: “Concentrating on personal finance don’ts is a clever idea . . . an intriguing reminder of what not to do when investing your money.” —The New York Times Brilliant investors and top businesspeople make mistakes, too—very expensive ones. Drawing on his twenty-plus years of experience at some of Wall Street’s most prestigious firms, as well as original research and interviews with these legendary investors, Stephen Weiss offers fascinating narrative accounts of their billion-dollar blunders. Here, such prominent figures as Kirk Kerkorian, Bill Ackman, David Bonderman, Aubrey McClendon, and Leon Cooperman discuss the most significant trade or investment that went against them, the magnitude of the loss, its effect on their businesses—and on their personal lives. The book skillfully examines the causal relationship between the quirks of each investor’s personality and the mistakes they have committed—as well as the lessons learned. While some investors made errors of judgment, others made errors of perception. But no matter how many zeros were attached to these particular losses, investors at any level can profit from the wisdom gained—and avoid the same missteps. “When a great investor flubs it, everyone can learn a lesson. With that in mind, author Stephen Weiss delves into the biggest mistakes of such Wall Street luminaries as Bill Ackman, Leon Cooperman and Richard Pzena.” —Barron’s