It was the 17th of September 1986, and the curtain was now coming down on the greed-is-good Wall Street boom. On the surface, nothing seemed much different in the high-flying world of leveraged buyouts, corporate raiders, junk bonds and suspendered yuppies chasing dizzying amounts of money. But behind the scenes, one of the icons of this era was cutting a deal with federal agents and an ambitious U.S. Attorney named Rudolph Giuliani in the biggest insider-trading investigation in history. Ivan Boesky, the mega-rich and super-arrogant 49-year-old king of the arbitragers, was agreeing to sing like a platinum canary to get...